CVE-2026-31465

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-04-22. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

writeback: don't block sync for filesystems with no data integrity guarantees

Add a SB_I_NO_DATA_INTEGRITY superblock flag for filesystems that cannot guarantee data persistence on sync (eg fuse). For superblocks with this flag set, sync kicks off writeback of dirty inodes but does not wait for the flusher threads to complete the writeback.

This replaces the per-inode AS_NO_DATA_INTEGRITY mapping flag added in commit f9a49aa302a0 ("fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes()"). The flag belongs at the superblock level because data integrity is a filesystem-wide property, not a per-inode one. Having this flag at the superblock level also allows us to skip having to iterate every dirty inode in wait_sb_inodes() only to skip each inode individually.

Prior to this commit, mappings with no data integrity guarantees skipped waiting on writeback completion but still waited on the flusher threads to finish initiating the writeback. Waiting on the flusher threads is unnecessary. This commit kicks off writeback but does not wait on the flusher threads. This change properly addresses a recent report [1] for a suspend-to-RAM hang seen on fuse-overlayfs that was caused by waiting on the flusher threads to finish:

Workqueue: pm_fs_sync pm_fs_sync_work_fn Call Trace: __schedule+0x457/0x1720 schedule+0x27/0xd0 wb_wait_for_completion+0x97/0xe0 sync_inodes_sb+0xf8/0x2e0 __iterate_supers+0xdc/0x160 ksys_sync+0x43/0xb0 pm_fs_sync_work_fn+0x17/0xa0 process_one_work+0x193/0x350 worker_thread+0x1a1/0x310 kthread+0xfc/0x240 ret_from_fork+0x243/0x280 ret_from_fork_asm+0x1a/0x30

On fuse this is problematic because there are paths that may cause the flusher thread to block (eg if systemd freezes the user session cgroups first, which freezes the fuse daemon, before invoking the kernel suspend. The kernel suspend triggers ->write_node() which on fuse issues a synchronous setattr request, which cannot be processed since the daemon is frozen. Or if the daemon is buggy and cannot properly complete writeback, initiating writeback on a dirty folio already under writeback leads to writeback_get_folio() -> folio_prepare_writeback() -> unconditional wait on writeback to finish, which will cause a hang). This commit restores fuse to its prior behavior before tmp folios were removed, where sync was essentially a no-op.

[1] https://lore.kernel.org/linux-fsdevel/CAJnrk1a-asuvfrbKXbEwwDSctvemF+6zfhdnuzO65Pt8HsFSRw@mail.gmail.com/T/#m632c4648e9cafc4239299887109ebd880ac6c5c1

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

April 22, 2026

Last Modified

May 7, 2026

Advisory Details (3)

Auto-updated Jun 14, 2026
No patch confirmed yet.
generic

writeback: don't block sync for filesystems with no data integrity guarantees - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/83800f8ef358ea2fc9b1ae4986b83f2bc24be927
generic

writeback: don't block sync for filesystems with no data integrity guarantees - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/76f9377cd2ab7a9220c25d33940d9ca20d368172
generic

writeback: don't block sync for filesystems with no data integrity guarantees - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5c24a13d8a0466ca0446e58309e51f2606520164

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.18.21—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.

Data Freshness Timeline

(refreshed 10× in last 7d / 38× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 122 total refreshes for this CVE.

  1. 2026-07-25 14:18 UTCEPSS rescore
  2. 2026-07-25 14:17 UTCEPSS rescore
  3. 2026-07-24 14:17 UTCEPSS rescore
  4. 2026-07-23 14:18 UTCEPSS rescore
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  6. 2026-07-23 03:08 UTCEG score recompute
  7. 2026-07-22 14:08 UTCEPSS rescore
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  9. 2026-07-21 15:24 UTCEPSS rescore
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  11. 2026-07-20 04:10 UTCOSV refresh
  12. 2026-07-19 14:31 UTCEPSS rescore
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  14. 2026-07-19 02:29 UTCEPSS rescore
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  24. 2026-07-12 05:46 UTCEPSS rescore
  25. 2026-07-11 08:27 UTCEPSS rescore
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  1. 2026-07-09 19:10 UTCEPSS rescore
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  3. 2026-07-07 13:46 UTCEPSS rescore
  4. 2026-07-06 16:27 UTCEPSS rescore
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  6. 2026-07-06 02:23 UTCEPSS rescore
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  10. 2026-07-01 15:06 UTCEPSS rescore
  11. 2026-06-30 23:22 UTCEPSS rescore
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  18. 2026-06-27 03:08 UTCEPSS rescore
  19. 2026-06-25 13:49 UTCEPSS rescore
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  21. 2026-06-24 14:05 UTCEPSS rescore
  22. 2026-06-23 21:33 UTCEPSS rescore
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  24. 2026-06-21 14:56 UTCEPSS rescore
  25. 2026-06-21 14:56 UTCEPSS rescore
  26. 2026-06-21 01:59 UTCEPSS rescore
  27. 2026-06-19 19:25 UTCEPSS rescore
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  29. 2026-06-18 17:52 UTCEPSS rescore
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  34. 2026-06-14 23:18 UTCEPSS rescore
  35. 2026-06-14 16:51 UTCGHSA enrichment
  36. 2026-06-13 23:00 UTCEPSS rescore
  37. 2026-06-12 23:12 UTCEPSS rescore
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  39. 2026-06-11 14:49 UTCGHSA enrichment
  40. 2026-06-11 14:00 UTCEPSS rescore
  41. 2026-06-10 22:18 UTCEPSS rescore
  42. 2026-06-10 13:22 UTCEPSS rescore
  43. 2026-06-10 11:55 UTCGHSA enrichment
  44. 2026-06-09 09:49 UTCGHSA enrichment
  45. 2026-06-08 14:17 UTCEPSS rescore
  46. 2026-06-08 14:17 UTCEPSS rescore
  47. 2026-06-08 04:16 UTCGHSA enrichment
  48. 2026-06-07 15:25 UTCEPSS rescore
  49. 2026-06-07 15:25 UTCEPSS rescore
  50. 2026-06-07 15:25 UTCEPSS rescore
  51. 2026-06-07 02:09 UTCGHSA enrichment
  52. 2026-06-06 13:47 UTCEPSS rescore
  53. 2026-06-06 13:47 UTCEPSS rescore
  54. 2026-06-06 00:03 UTCGHSA enrichment
  55. 2026-06-05 22:47 UTCEPSS rescore
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  57. 2026-06-05 06:10 UTCEPSS rescore
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  59. 2026-06-04 21:33 UTCGHSA enrichment
  60. 2026-06-04 13:12 UTCEPSS rescore
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  62. 2026-06-03 19:22 UTCGHSA enrichment
  63. 2026-06-02 20:13 UTCEPSS rescore
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  65. 2026-06-02 17:15 UTCGHSA enrichment
  66. 2026-06-01 15:08 UTCGHSA enrichment
  67. 2026-06-01 13:51 UTCEPSS rescore
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  75. 2026-05-28 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-31465?
CVE-2026-31465 is a medium vulnerability published on April 22, 2026. In the Linux kernel, the following vulnerability has been resolved: writeback: don't block sync for filesystems with no data integrity guarantees Add a SBINODATAINTEGRITY superblock flag for filesystems that cannot guarantee data persistence on sync (eg fuse). For superblocks with this flag set,…
When was CVE-2026-31465 disclosed?
CVE-2026-31465 was first published in the National Vulnerability Database on April 22, 2026, with the most recent update on May 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31465 actively exploited?
CVE-2026-31465 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.8% of all scored CVEs.
What is the CVSS score of CVE-2026-31465?
CVE-2026-31465 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-31465?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31465, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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