CVE-2026-31664

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-04-24. 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:

xfrm: clear trailing padding in build_polexpire()

build_expire() clears the trailing padding bytes of struct xfrm_user_expire after setting the hard field via memset_after(), but the analogous function build_polexpire() does not do this for struct xfrm_user_polexpire.

The padding bytes after the __u8 hard field are left uninitialized from the heap allocation, and are then sent to userspace via netlink multicast to XFRMNLGRP_EXPIRE listeners, leaking kernel heap memory contents.

Add the missing memset_after() call, matching build_expire().

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 24, 2026

Last Modified

July 14, 2026

Advisory Details (10)

Auto-updated Jul 19, 2026
⚠️ Active exploitation confirmed. No patch confirmed yet.
generic🔴 Active Exploitation

SSA-082556

https://cert-portal.siemens.com/productcert/html/ssa-082556.html
generic

SSA-019113

https://cert-portal.siemens.com/productcert/html/ssa-019113.html
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/eda30846ea54f8ed218468e5480c8305ca645e37
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e6f4ffe8596947a595c9544e73a73adcb0568b88
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e1af65c669ebb1666c54576614c01a7f9ffcfff6
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c221ed63a2769a0af8bd849dfe25740048f34ef4
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b1dfd6b27df35ef4f87825aa5f607378d23ff0f2
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ac6985903db047eaff54db929e4bf6b06782788e
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a5127501c8d30b5728791b1e340284ca5c9cc4bd
generic

xfrm: clear trailing padding in build_polexpire() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/71a98248c63c535eaa4d4c22f099b68d902006d0

Vendor Advisories for CVE-2026-31664(2)

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 / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 5.10.258—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 rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (54 versions)5.10.259-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.164-1~deb11u1 (16 versions)6.1.170-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (48 versions)6.1.170-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (124 versions)6.19.13-1—

Additional Vendor Advisories

(24)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 51× 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 212 total refreshes for this CVE.

  1. 2026-09-04 05:06 UTCEPSS rescore
  2. 2026-09-04 03:16 UTCOSV refresh
  3. 2026-09-02 14:11 UTCEPSS rescore
  4. 2026-09-01 13:53 UTCEPSS rescore
  5. 2026-09-01 04:39 UTCEPSS rescore
  6. 2026-09-01 04:39 UTCEPSS rescore
  7. 2026-08-30 19:17 UTCEPSS rescore
  8. 2026-08-28 21:41 UTCEPSS rescore
  9. 2026-08-27 14:25 UTCEPSS rescore
  10. 2026-08-26 14:46 UTCEPSS rescore
  11. 2026-08-25 13:49 UTCEPSS rescore
  12. 2026-08-24 14:17 UTCEPSS rescore
  13. 2026-08-23 00:19 UTCEPSS rescore
  14. 2026-08-20 22:55 UTCEPSS rescore
  15. 2026-08-20 22:55 UTCEPSS rescore
  16. 2026-08-19 17:03 UTCEPSS rescore
  17. 2026-08-18 13:48 UTCEPSS rescore
  18. 2026-08-17 14:48 UTCEG score recompute
  19. 2026-08-17 14:48 UTCVendor advisory
  20. 2026-08-17 14:48 UTCGHSA enrichment
  21. 2026-08-17 13:47 UTCEPSS rescore
  22. 2026-08-16 14:56 UTCEPSS rescore
  23. 2026-08-16 05:46 UTCEG score recompute
  24. 2026-08-16 05:46 UTCVendor advisory
  25. 2026-08-16 05:46 UTCGHSA enrichment
Show 75 more
  1. 2026-08-16 02:14 UTCEPSS rescore
  2. 2026-08-15 01:30 UTCEPSS rescore
  3. 2026-08-14 04:06 UTCEG score recompute
  4. 2026-08-14 04:06 UTCVendor advisory
  5. 2026-08-14 04:06 UTCGHSA enrichment
  6. 2026-08-13 22:00 UTCEPSS rescore
  7. 2026-08-12 17:48 UTCEG score recompute
  8. 2026-08-12 17:48 UTCVendor advisory
  9. 2026-08-12 17:48 UTCGHSA enrichment
  10. 2026-08-12 13:50 UTCEPSS rescore
  11. 2026-08-11 07:20 UTCEG score recompute
  12. 2026-08-11 07:20 UTCVendor advisory
  13. 2026-08-11 07:20 UTCGHSA enrichment
  14. 2026-08-11 00:00 UTCEPSS rescore
  15. 2026-08-10 05:19 UTCEG score recompute
  16. 2026-08-10 05:19 UTCVendor advisory
  17. 2026-08-10 05:19 UTCGHSA enrichment
  18. 2026-08-09 13:46 UTCEPSS rescore
  19. 2026-08-09 03:18 UTCEG score recompute
  20. 2026-08-09 03:18 UTCVendor advisory
  21. 2026-08-09 03:18 UTCGHSA enrichment
  22. 2026-08-08 16:37 UTCEPSS rescore
  23. 2026-08-07 12:32 UTCEG score recompute
  24. 2026-08-07 12:32 UTCVendor advisory
  25. 2026-08-07 12:32 UTCGHSA enrichment
  26. 2026-08-06 13:46 UTCEPSS rescore
  27. 2026-08-05 22:55 UTCEG score recompute
  28. 2026-08-05 22:55 UTCVendor advisory
  29. 2026-08-05 22:55 UTCGHSA enrichment
  30. 2026-08-05 19:17 UTCEPSS rescore
  31. 2026-08-04 15:10 UTCEPSS rescore
  32. 2026-08-04 10:38 UTCEPSS rescore
  33. 2026-08-03 21:00 UTCEG score recompute
  34. 2026-08-03 21:00 UTCVendor advisory
  35. 2026-08-03 21:00 UTCGHSA enrichment
  36. 2026-08-03 10:36 UTCEPSS rescore
  37. 2026-08-02 11:09 UTCEG score recompute
  38. 2026-08-02 11:09 UTCVendor advisory
  39. 2026-08-02 11:09 UTCGHSA enrichment
  40. 2026-08-02 02:27 UTCEPSS rescore
  41. 2026-08-01 04:16 UTCEPSS rescore
  42. 2026-07-30 16:28 UTCEPSS rescore
  43. 2026-07-30 01:30 UTCEPSS rescore
  44. 2026-07-28 15:36 UTCEPSS rescore
  45. 2026-07-26 14:54 UTCEPSS rescore
  46. 2026-07-26 14:54 UTCEPSS rescore
  47. 2026-07-25 14:18 UTCEPSS rescore
  48. 2026-07-25 14:17 UTCEPSS rescore
  49. 2026-07-24 14:17 UTCEPSS rescore
  50. 2026-07-23 14:18 UTCEPSS rescore
  51. 2026-07-23 14:18 UTCEPSS rescore
  52. 2026-07-23 03:08 UTCEG score recompute
  53. 2026-07-22 14:08 UTCEPSS rescore
  54. 2026-07-22 14:08 UTCEPSS rescore
  55. 2026-07-21 15:24 UTCEPSS rescore
  56. 2026-07-21 15:24 UTCEPSS rescore
  57. 2026-07-20 17:08 UTCEPSS rescore
  58. 2026-07-20 17:08 UTCEPSS rescore
  59. 2026-07-19 23:08 UTCOSV refresh
  60. 2026-07-19 14:31 UTCEPSS rescore
  61. 2026-07-19 14:31 UTCEPSS rescore
  62. 2026-07-19 02:29 UTCEPSS rescore
  63. 2026-07-18 10:04 UTCEPSS rescore
  64. 2026-07-18 10:04 UTCEPSS rescore
  65. 2026-07-16 17:03 UTCEPSS rescore
  66. 2026-07-16 17:03 UTCEPSS rescore
  67. 2026-07-15 16:57 UTCEPSS rescore
  68. 2026-07-15 16:57 UTCEPSS rescore
  69. 2026-07-15 02:00 UTCEPSS rescore
  70. 2026-07-15 02:00 UTCEPSS rescore
  71. 2026-07-14 13:19 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  72. 2026-07-14 13:11 UTCMITRE cvelistV5
  73. 2026-07-13 22:30 UTCEPSS rescore
  74. 2026-07-13 06:13 UTCEPSS rescore
  75. 2026-07-13 06:13 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-31664?
CVE-2026-31664 is a medium vulnerability published on April 24, 2026. In the Linux kernel, the following vulnerability has been resolved: xfrm: clear trailing padding in build_polexpire() build_expire() clears the trailing padding bytes of struct xfrmuserexpire after setting the hard field via memset_after(), but the analogous function build_polexpire() does not do…
When was CVE-2026-31664 disclosed?
CVE-2026-31664 was first published in the National Vulnerability Database on April 24, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-31664 actively exploited?
CVE-2026-31664 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 98.0% of all scored CVEs.
What is the CVSS score of CVE-2026-31664?
CVE-2026-31664 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-31664?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-31664, 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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-31664

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