CVE-2026-72137

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreHIGH confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-15. a secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: 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: nat_keepalive: avoid double free on send error

nat_keepalive_send() frees the keepalive skb whenever the IPv4 or IPv6 send helper reports an error.

That cleanup is only correct before the skb is handed to the output path. Once ip_build_and_send_pkt() or ip6_xmit() takes ownership, the networking stack may already have consumed the skb before returning an error, so freeing it again is unsafe.

Handle the pre-handoff failure cases inside nat_keepalive_send_ipv4() and nat_keepalive_send_ipv6(), where the caller still owns the skb, and keep nat_keepalive_send() responsible only for family dispatch and the unsupported-family cleanup path.

CVSS v3
9.8
EG Score
9.8(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity98% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
47%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 17, 2026

Advisory Details (4)

Auto-updated Aug 17, 2026
No patch confirmed yet.
generic

xfrm: nat_keepalive: avoid double free on send error - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d0a4dc7efa825bce60a8da8f7d43c864a159abde
generic

xfrm: nat_keepalive: avoid double free on send error - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a8a7e6a9ff8a4c1f067694ddbd44be67fdf36693
generic

xfrm: nat_keepalive: avoid double free on send error - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5b0c4c916f202b8fd13d12afb6af62b385622f81
generic

xfrm: nat_keepalive: avoid double free on send error - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/226f4a490d1a938fc838d8f8c46a4eca864c0d78

Vendor Advisories for CVE-2026-72137(1)

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

Data Freshness Timeline

(refreshed 49× in last 7d / 49× 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.

  1. 2026-08-21 07:20 UTCGHSA enrichment
  2. 2026-08-21 03:20 UTCGHSA enrichment
  3. 2026-08-20 23:20 UTCEG score recompute
  4. 2026-08-20 23:20 UTCGHSA enrichment
  5. 2026-08-20 22:56 UTCEPSS rescore
  6. 2026-08-20 19:21 UTCGHSA enrichment
  7. 2026-08-20 15:21 UTCGHSA enrichment
  8. 2026-08-20 11:22 UTCGHSA enrichment
  9. 2026-08-20 07:22 UTCGHSA enrichment
  10. 2026-08-20 03:22 UTCGHSA enrichment
  11. 2026-08-19 23:22 UTCGHSA enrichment
  12. 2026-08-19 19:22 UTCEG score recompute
  13. 2026-08-19 19:22 UTCGHSA enrichment
  14. 2026-08-19 17:04 UTCEPSS rescore
  15. 2026-08-19 15:20 UTCGHSA enrichment
  16. 2026-08-19 11:15 UTCGHSA enrichment
  17. 2026-08-19 07:14 UTCGHSA enrichment
  18. 2026-08-19 03:13 UTCGHSA enrichment
  19. 2026-08-18 23:11 UTCGHSA enrichment
  20. 2026-08-18 19:11 UTCGHSA enrichment
  21. 2026-08-18 15:11 UTCEG score recompute
  22. 2026-08-18 15:11 UTCGHSA enrichment
  23. 2026-08-18 13:49 UTCEPSS rescore
  24. 2026-08-18 13:49 UTCEPSS rescore
  25. 2026-08-18 11:04 UTCGHSA enrichment
Show 24 more
  1. 2026-08-18 07:03 UTCGHSA enrichment
  2. 2026-08-18 03:01 UTCGHSA enrichment
  3. 2026-08-17 23:01 UTCGHSA enrichment
  4. 2026-08-17 19:01 UTCGHSA enrichment
  5. 2026-08-17 14:18 UTCEG score recompute
  6. 2026-08-17 14:18 UTCGHSA enrichment
  7. 2026-08-17 13:47 UTCEPSS rescore
  8. 2026-08-17 10:18 UTCEG score recompute
  9. 2026-08-17 10:18 UTCGHSA enrichment
  10. 2026-08-17 06:18 UTCEG score recompute
  11. 2026-08-17 06:18 UTCGHSA enrichment
  12. 2026-08-17 06:00 UTCEG score recompute▲ 9.80
  13. 2026-08-17 06:00 UTCGHSA enrichment
  14. 2026-08-17 05:54 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  15. 2026-08-17 05:33 UTCEG score recompute
  16. 2026-08-17 05:33 UTCGHSA enrichment
  17. 2026-08-17 05:24 UTCMITRE cvelistV5
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 14:56 UTCEPSS rescore
  20. 2026-08-16 02:15 UTCEPSS rescore
  21. 2026-08-15 06:42 UTCGHSA enrichment
  22. 2026-08-15 06:23 UTCNVD update
  23. 2026-08-15 06:11 UTCEG score recompute
  24. 2026-08-15 06:02 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-72137?
CVE-2026-72137 is a critical vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: xfrm: nat_keepalive: avoid double free on send error natkeepalivesend() frees the keepalive skb whenever the IPv4 or IPv6 send helper reports an error. That cleanup is only correct before the skb is handed to the output path. Once…
When was CVE-2026-72137 disclosed?
CVE-2026-72137 was first published in the National Vulnerability Database on August 15, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-72137 actively exploited?
CVE-2026-72137 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 52.6% of all scored CVEs.
What is the CVSS score of CVE-2026-72137?
CVE-2026-72137 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-72137?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-72137, 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

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