CVE-2026-31456

MEDIUMNVD 4.74.7
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 4.7 from GitHub Security Advisory published 2026-04-22. NVD baseline CVSS 4.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-24795 (ENISA EUVD) · GHSA-x569-m75g-6pr8 (GitHub Security Advisories)Source: ENISA EUVD

4.7EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: <0.1%CVSS: 4.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

mm/pagewalk: fix race between concurrent split and refault

The splitting of a PUD entry in walk_pud_range() can race with a concurrent thread refaulting the PUD leaf entry causing it to try walking a PMD range that has disappeared.

An example and reproduction of this is to try reading numa_maps of a process while VFIO-PCI is setting up DMA (specifically the vfio_pin_pages_remote call) on a large BAR for that process.

This will trigger a kernel BUG: vfio-pci 0000:03:00.0: enabling device (0000 -> 0002) BUG: unable to handle page fault for address: ffffa23980000000 PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI ... RIP: 0010:walk_pgd_range+0x3b5/0x7a0 Code: 8d 43 ff 48 89 44 24 28 4d 89 ce 4d 8d a7 00 00 20 00 48 8b 4c 24 28 49 81 e4 00 00 e0 ff 49 8d 44 24 ff 48 39 c8 4c 0f 43 e3 <49> f7 06 9f ff ff ff 75 3b 48 8b 44 24 20 48 8b 40 28 48 85 c0 74 RSP: 0018:ffffac23e1ecf808 EFLAGS: 00010287 RAX: 00007f44c01fffff RBX: 00007f4500000000 RCX: 00007f44ffffffff RDX: 0000000000000000 RSI: 000ffffffffff000 RDI: ffffffff93378fe0 RBP: ffffac23e1ecf918 R08: 0000000000000004 R09: ffffa23980000000 R10: 0000000000000020 R11: 0000000000000004 R12: 00007f44c0200000 R13: 00007f44c0000000 R14: ffffa23980000000 R15: 00007f44c0000000 FS: 00007fe884739580(0000) GS:ffff9b7d7a9c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffa23980000000 CR3: 000000c0650e2005 CR4: 0000000000770ef0 PKRU: 55555554 Call Trace: __walk_page_range+0x195/0x1b0 walk_page_vma+0x62/0xc0 show_numa_map+0x12b/0x3b0 seq_read_iter+0x297/0x440 seq_read+0x11d/0x140 vfs_read+0xc2/0x340 ksys_read+0x5f/0xe0 do_syscall_64+0x68/0x130 ? get_page_from_freelist+0x5c2/0x17e0 ? mas_store_prealloc+0x17e/0x360 ? vma_set_page_prot+0x4c/0xa0 ? __alloc_pages_noprof+0x14e/0x2d0 ? __mod_memcg_lruvec_state+0x8d/0x140 ? __lruvec_stat_mod_folio+0x76/0xb0 ? __folio_mod_stat+0x26/0x80 ? do_anonymous_page+0x705/0x900 ? __handle_mm_fault+0xa8d/0x1000 ? __count_memcg_events+0x53/0xf0 ? handle_mm_fault+0xa5/0x360 ? do_user_addr_fault+0x342/0x640 ? arch_exit_to_user_mode_prepare.constprop.0+0x16/0xa0 ? irqentry_exit_to_user_mode+0x24/0x100 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7fe88464f47e Code: c0 e9 b6 fe ff ff 50 48 8d 3d be 07 0b 00 e8 69 01 02 00 66 0f 1f 84 00 00 00 00 00 64 8b 04 25 18 00 00 00 85 c0 75 14 0f 05 <48> 3d 00 f0 ff ff 77 5a c3 66 0f 1f 84 00 00 00 00 00 48 83 ec 28 RSP: 002b:00007ffe6cd9a9b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000020000 RCX: 00007fe88464f47e RDX: 0000000000020000 RSI: 00007fe884543000 RDI: 0000000000000003 RBP: 00007fe884543000 R08: 00007fe884542010 R09: 0000000000000000 R10: fffffffffffffbc5 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000003 R14: 0000000000020000 R15: 0000000000020000

Fix this by validating the PUD entry in walk_pmd_range() using a stable snapshot (pudp_get()). If the PUD is not present or is a leaf, retry the walk via ACTION_AGAIN instead of descending further. This mirrors the retry logic in walk_pte_range(), which lets walk_pmd_range() retry if the PTE is not being got by pte_offset_map_lock().

CVSS v3
4.7
EG Score
4.7MEDIUMmedium confidence
EG Risk
21
EG Risk 21/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity47% × 45%
Impact severity (EG Severity): CVSS 4.7 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
<0.1%
EPSS %ILE
below the 1st
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (4.7): severity, escalated by confirmed exploitation. This CVE's 4.7 is its impact severity (EG Severity), not escalated.

EG Severity
4.7 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
<0.1% within 30 daysSource: FIRST EPSS. FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

April 22, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Aug 2, 2026
Patch available.
Web page

mm/pagewalk: fix race between concurrent split and refault - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/9bbbebd94dd5be25ec8c899d46ef01b33d5d22c0
Web page

mm/pagewalk: fix race between concurrent split and refault - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3b89863c3fa482912911cd65a12a3aeef662c250
Web page

mm/pagewalk: fix race between concurrent split and refault - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/38ec58670a0c5fc1edabdeccd857e586b7b3f318
Web page

mm/pagewalk: fix race between concurrent split and refault - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/138ada1337b47cc5efb08e517674d46f86268274

Vendor Advisories for CVE-2026-31456(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
linuxKernel @ 6.12.84 (fixes >=6.12.0)—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 2 ecosystems)
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)
  • every version up to 6.12.85-1: fixed in 6.12.85-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (125 versions)
  • every version up to 6.19.11-1: fixed in 6.19.11-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 35× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 95 of 195 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 5 repeat rows among the latest 100 are merged into the row they repeat. The 100 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 16:33 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  2. 2026-10-28 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  3. 2026-10-27 16:31 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  4. 2026-10-25 16:32 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  5. 2026-10-25 14:36 UTCEG score recompute
  6. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  7. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  8. 2026-10-23 03:52 UTCEG score recompute
  9. 2026-10-23 03:52 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  10. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  11. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  12. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  13. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  14. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  15. 2026-10-18 03:48 UTCEG score recompute
  16. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  17. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  18. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  19. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  20. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  21. 2026-10-12 16:15 UTCEG score recompute
  22. 2026-10-11 19:57 UTCEG score recompute
  23. 2026-10-11 17:11 UTCEG score recompute
  24. 2026-10-11 14:39 UTCEG score recompute
  25. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.1% · 1st percentile
Show 70 more
  1. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  2. 2026-10-10 18:03 UTCOSV refresh
  3. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  4. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  6. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  7. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  8. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  9. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  10. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  11. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  12. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  13. 2026-09-26 00:26 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  14. 2026-09-21 05:19 UTCOSV refresh
  15. 2026-09-18 19:27 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  16. 2026-09-17 19:30 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  17. 2026-09-16 14:08 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  18. 2026-09-12 15:01 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  19. 2026-09-11 14:52 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  20. 2026-09-10 09:34 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  21. 2026-09-08 22:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  22. 2026-09-02 14:11 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  23. 2026-09-02 03:04 UTCOSV refresh
  24. 2026-09-01 13:53 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  25. 2026-08-30 19:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  26. 2026-08-28 21:41 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  27. 2026-08-27 14:25 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  28. 2026-08-26 14:46 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  29. 2026-08-25 13:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  30. 2026-08-24 14:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  31. 2026-08-23 00:19 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  32. 2026-08-21 23:49 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  33. 2026-08-20 22:55 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  34. 2026-08-18 13:48 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  35. 2026-08-17 13:47 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  36. 2026-08-16 14:56 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  37. 2026-08-16 06:01 UTCEG score recompute
  38. 2026-08-16 06:01 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  39. 2026-08-16 02:14 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  40. 2026-08-15 01:30 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  41. 2026-08-14 04:20 UTCEG score recompute
  42. 2026-08-14 04:20 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  43. 2026-08-13 22:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  44. 2026-08-12 18:32 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  45. 2026-08-11 05:16 UTCEG score recompute
  46. 2026-08-11 05:16 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  47. 2026-08-11 00:00 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  48. 2026-08-10 04:24 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  49. 2026-08-09 03:33 UTCEG score recompute
  50. 2026-08-09 03:33 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  51. 2026-08-08 16:37 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  52. 2026-08-07 12:50 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  53. 2026-08-05 23:05 UTCEG score recompute
  54. 2026-08-05 23:05 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  55. 2026-08-05 19:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  56. 2026-08-04 15:10 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  57. 2026-08-03 21:15 UTCEG score recompute
  58. 2026-08-03 21:15 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  59. 2026-08-03 10:36 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  60. 2026-08-02 12:31 UTCEG score recompute
  61. 2026-08-02 12:31 UTCGHSA enrichmentGHSA-x569-m75g-6pr8 · GitHub CVSS 4.7
  62. 2026-08-02 02:27 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  63. 2026-08-01 04:16 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  64. 2026-07-28 15:36 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  65. 2026-07-26 14:54 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  66. 2026-07-25 14:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  67. 2026-07-24 14:17 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  68. 2026-07-23 03:08 UTCEG score recompute
  69. 2026-07-22 14:08 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile
  70. 2026-07-20 17:08 UTCEPSS rescoreEPSS <0.1% · below the 1st percentile

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-31456?
CVE-2026-31456 is a medium-severity vulnerability; its CVE record was published on April 22, 2026. In the Linux kernel, the following vulnerability has been resolved: mm/pagewalk: fix race between concurrent split and refault The splitting of a PUD entry in walkpudrange() can race with a concurrent thread refaulting the PUD leaf entry causing it to try walking a PMD range that has disappeared.…
When was the CVE record for CVE-2026-31456 published?
The CVE record for CVE-2026-31456 was published on April 22, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of June 17, 2026; the record at its source may have been updated since.
Is CVE-2026-31456 actively exploited?
CVE-2026-31456 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a <0.1% probability of exploitation in the next 30 days (below the 1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-31456?
CVE-2026-31456 has a CVSS v3 base score of 4.7 (NVD).
How do I remediate CVE-2026-31456?
A fix for CVE-2026-31456 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-31456 are linked in the Vendor Advisories panel on this page.

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