CVE-2026-45991

HIGHPre-NVD 7.87.8
EchelonGraph scoreMEDIUM confidence

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

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-05-27. A secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

udf: fix partition descriptor append bookkeeping

Mounting a crafted UDF image with repeated partition descriptors can trigger a heap out-of-bounds write in part_descs_loc[].

handle_partition_descriptor() deduplicates entries by partition number, but appended slots never record partnum. As a result duplicate Partition Descriptors are appended repeatedly and num_part_descs keeps growing.

Once the table is full, the growth path still sizes the allocation from partnum even though inserts are indexed by num_part_descs. If partnum is already aligned to PART_DESC_ALLOC_STEP, ALIGN(partnum, step) can keep the old capacity and the next append writes past the end of the table.

Store partnum in the appended slot and size growth from the next append count so deduplication and capacity tracking follow the same model.

CVSS v3
7.8
EG Score
7.8HIGHmedium confidence
EG Risk
35
EG Risk 35/100

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)
Severity78% × 45%
Impact severity (EG Severity): CVSS 7.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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
0.2%
EPSS %ILE
6th
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 (7.8): severity, escalated by confirmed exploitation. This CVE's 7.8 is its impact severity (EG Severity), not escalated.

EG Severity
7.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-19). 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 (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (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 Vulnrichment) · Technical impact total (CISA Vulnrichment). 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

May 27, 2026

Last Modified

October 19, 2026

Advisory Details (4)

Auto-updated Jun 3, 2026
Patch available.
Web page

udf: fix partition descriptor append bookkeeping - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b5597bb83fc37b5b5da74a4453fa920b932cf39a
Web page

udf: fix partition descriptor append bookkeeping - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/08fa5d818e5bf53c7ca234d88ba334f32004e9b6
Web page

udf: fix partition descriptor append bookkeeping - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/08841b06fa64d8edbd1a21ca6e613420c90cc4b8
Web page

udf: fix partition descriptor append bookkeeping - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/058b451b1039f056d1362c4fec2229e522366ab0

Patch Availability(31)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-virtual-6.8 (6.8.0-136.136) @ noble2026-10-19ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1058.61) @ noble2026-10-19ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1059.62.1) @ noble2026-10-19ubuntu
ubuntulinux-virtual-hwe-24.04-edge (7.0.0-28.28~24.04.1) @ noble2026-10-19ubuntu
ubuntulinux-tools-aws-lts-24.04 (6.8.0-1061.64+1) @ noble2026-10-19ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1063.71) @ noble2026-10-19ubuntu
ubuntulinux-tools-azure-fde-lts-24.04 (6.8.0-1062.69) @ noble2026-10-19ubuntu
ubuntulinux-tools-azure-fips-6.8 (6.8.0-1063.71+fips2) @ noble2026-10-19ubuntu
ubuntulinux-tools-azure-fde-6.8 (6.8.0-1062.69~22.04.1) @ jammy2026-10-19ubuntu
ubuntulinux-tools-aws-fips-6.8 (6.8.0-1061.64+fips1) @ noble2026-10-19ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1033.34) @ noble2026-10-19ubuntu
ubuntulinux-virtual-hwe-22.04-edge (6.8.0-136.136~22.04.1) @ jammy2026-10-19ubuntu
ubuntulinux-tools-oracle-edge (5.15.0.1114.120~20.04.1) @ focal2026-10-19ubuntu
ubuntulinux-tools-gcp-lts-22.04 (5.15.0.1118.115) @ jammy2026-10-19ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1080 (5.15.0-1080.84) @ jammy2026-10-19ubuntu
ubuntulinux-tools-nvidia-lowlatency-5.15 (5.15.0.1112.112) @ jammy2026-10-19ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1064.72+fips1) @ noble2026-10-19ubuntu
ubuntulinux-tools-raspi-realtime-7.0 (7.0.0-1014.14) @ resolute2026-10-19ubuntu
ubuntulinux-tools-gcp-edge (5.15.0.1118.128~20.04.1) @ focal2026-10-19ubuntu
ubuntulinux-tools-oem-7.0 (7.0.0-1008.8) @ resolute2026-10-19ubuntu
ubuntulinux-tools-oracle-edge (6.8.0-1058.61~22.04.1) @ jammy2026-10-19ubuntu
ubuntulinux-tools-azure-fde-7.0 (7.0.0-1009.9) @ resolute2026-10-19ubuntu
ubuntulinux-tools-azure-fde-lts-22.04 (5.15.0.1122.131) @ jammy2026-10-19ubuntu
redhatkernel-0:6.12.0-55.109.1.el10_02026-10-08redhat
redhatkernel-0:4.18.0-372.220.1.el8_62026-10-07redhat
redhatkernel-0:4.18.0-305.211.1.el8_42026-10-07redhat
redhatkernel-0:5.14.0-687.41.1.el9_82026-08-20redhat
redhatkernel-0:6.12.0-211.49.1.el10_22026-08-20redhat
redhatkernel-0:4.18.0-553.155.1.el8_102026-08-12redhat
redhatkernel-rt-0:4.18.0-553.155.1.rt7.496.el8_102026-08-12redhat
linuxKernel @ 5.10.259 (fixes >=4.19.0)—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

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFix by version rangeDependents
linux5.10.103-1 ... 5.10.92-2 (54 versions)
  • every version up to 5.10.259-1: fixed in 5.10.259-1
—
linux-6.16.1.106-3~deb11u1 ... 6.1.174-1~deb11u1 (20 versions)
  • every version up to 6.1.176-1~deb11u1: fixed in 6.1.176-1~deb11u1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 6.1.99-1 (53 versions)
  • every version up to 6.1.176-1: fixed in 6.1.176-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.38-1 ... 6.12.88-1~bpo12+1 (21 versions)
  • every version up to 6.12.88-1: fixed in 6.12.88-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.0.4-1~bpo13+1 (135 versions)
  • every version up to 7.0.4-1: fixed in 7.0.4-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(17)

Data Freshness Timeline

(refreshed 32× in last 7d / 53× 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 100 of 347 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. None are among the latest 100 rows. The 247 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-19 20:33 UTCEG score recompute
  2. 2026-10-19 20:33 UTCVendor advisory
  3. 2026-10-19 20:33 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  4. 2026-10-19 19:31 UTCEG score recompute
  5. 2026-10-19 19:31 UTCVendor advisory
  6. 2026-10-19 19:31 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  7. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  8. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  9. 2026-10-18 03:37 UTCEG score recompute
  10. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  11. 2026-10-16 17:06 UTCEG score recompute
  12. 2026-10-16 17:06 UTCVendor advisory
  13. 2026-10-16 17:05 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  14. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  15. 2026-10-16 15:39 UTCEG score recompute
  16. 2026-10-16 15:39 UTCVendor advisory
  17. 2026-10-16 15:38 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  18. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-10-15 11:26 UTCEG score recompute
  20. 2026-10-15 11:26 UTCVendor advisory
  21. 2026-10-15 11:26 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  22. 2026-10-15 10:31 UTCEG score recompute
  23. 2026-10-15 10:31 UTCVendor advisory
  24. 2026-10-15 10:31 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  25. 2026-10-15 02:33 UTCEG score recompute
Show 75 more
  1. 2026-10-15 02:33 UTCVendor advisory
  2. 2026-10-15 02:33 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  3. 2026-10-15 01:36 UTCEG score recompute
  4. 2026-10-15 01:36 UTCVendor advisory
  5. 2026-10-15 01:36 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  6. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  7. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  8. 2026-10-12 16:03 UTCEG score recompute
  9. 2026-10-11 19:46 UTCEG score recompute
  10. 2026-10-11 17:00 UTCEG score recompute
  11. 2026-10-11 14:25 UTCEG score recompute
  12. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  13. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  14. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  15. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  16. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  17. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  18. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  19. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  20. 2026-10-03 18:21 UTCOSV refresh
  21. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  22. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  23. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  24. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  25. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  26. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  27. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  28. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  29. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  30. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  31. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  32. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  33. 2026-09-14 08:42 UTCEG score recompute
  34. 2026-09-14 08:42 UTCVendor advisory
  35. 2026-09-14 08:41 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  36. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  37. 2026-09-13 04:09 UTCOSV refresh
  38. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  39. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  40. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  41. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  42. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  43. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  44. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  45. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  46. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  47. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  48. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  49. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  50. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  51. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  52. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  53. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  54. 2026-08-25 05:33 UTCEG score recompute
  55. 2026-08-25 05:33 UTCVendor advisory
  56. 2026-08-25 05:32 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  57. 2026-08-23 15:23 UTCEG score recompute
  58. 2026-08-23 15:23 UTCVendor advisory
  59. 2026-08-23 15:23 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  60. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  61. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  62. 2026-08-21 20:45 UTCVendor advisory
  63. 2026-08-21 20:44 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  64. 2026-08-21 01:43 UTCEG score recompute
  65. 2026-08-21 01:43 UTCVendor advisory
  66. 2026-08-21 01:43 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  67. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  68. 2026-08-20 11:40 UTCEG score recompute
  69. 2026-08-20 11:40 UTCVendor advisory
  70. 2026-08-20 11:40 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8
  71. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  72. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  73. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  74. 2026-08-17 09:19 UTCVendor advisory
  75. 2026-08-17 09:19 UTCGHSA enrichmentGHSA-x889-prf3-g3vg · GitHub severity HIGH · GitHub CVSS 7.8

Frequently asked(5)

What is CVE-2026-45991?
CVE-2026-45991 is a high-severity vulnerability; its CVE record was published on May 27, 2026. In the Linux kernel, the following vulnerability has been resolved: udf: fix partition descriptor append bookkeeping Mounting a crafted UDF image with repeated partition descriptors can trigger a heap out-of-bounds write in partdescsloc[]. handlepartitiondescriptor() deduplicates entries by…
When was the CVE record for CVE-2026-45991 published?
The CVE record for CVE-2026-45991 was published on May 27, 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 October 19, 2026; the record at its source may have been updated since.
Is CVE-2026-45991 actively exploited?
CVE-2026-45991 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (6th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-45991?
CVE-2026-45991 has a CVSS base score of 7.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-45991?
A fix for CVE-2026-45991 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-45991 are linked in the Vendor Advisories panel on this page.

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