CVE-2026-72502

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-15. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: 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:

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)

When MTU is large, ip6_default_advmss() can return IPV6_MAXPLEN (65535). This is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535.

However, 0xFFFF is also used as a magic value GSO_BY_FRAGS in the kernel. If a TCP packet with gso_size=0xFFFF is passed to skb_segment(), it will be mistakenly treated as GSO_BY_FRAGS, leading to a NULL pointer dereference because local TCP packets do not use frag_list.

Fix this by returning min(IPV6_MAXPLEN, GSO_BY_FRAGS - 1) (65534) from ip6_default_advmss() when MTU is large.

Also update the stale comment in ip6_default_advmss() which suggested that IPV6_MAXPLEN is returned to mean "any MSS".

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
39(Track)
EG Risk 39/100SSVC: 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
Severity75% × 45%
Exploitation1% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
50%
KEV
Not listed

Published

August 15, 2026

Last Modified

August 17, 2026

Advisory Details (8)

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

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d774cdbda6634a78d0f2baf201ee5a8c57f3bc0e
generic

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c0db3dc2ac323b6c4b76adede3b355a9daa6dea8
generic

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/a210791f33345aa87187f7d7a9f3b9b7f4a28e6d
generic

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8e6214a530c03e341dc1b0a846c8f2b716b3551a
generic

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/572fff10819dfc359298d1f774839e76a4d96f93
generic

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/560b33b434e922ef97f9ff23aa2e909ef7aacd5c
generic

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22
generic

tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/21f69ac1879bb970588d5e7c12a96e6542f7c1a7

Vendor Advisories for CVE-2026-72502(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 30× in last 7d / 30× 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 00:06 UTCEG score recompute
  2. 2026-08-21 00:06 UTCGHSA enrichment
  3. 2026-08-20 22:56 UTCEPSS rescore
  4. 2026-08-20 11:17 UTCGHSA enrichment
  5. 2026-08-19 22:30 UTCEG score recompute
  6. 2026-08-19 22:30 UTCGHSA enrichment
  7. 2026-08-19 17:04 UTCEPSS rescore
  8. 2026-08-19 09:42 UTCGHSA enrichment
  9. 2026-08-18 20:54 UTCEG score recompute
  10. 2026-08-18 20:54 UTCGHSA enrichment
  11. 2026-08-18 13:49 UTCEPSS rescore
  12. 2026-08-18 13:49 UTCEPSS rescore
  13. 2026-08-18 08:06 UTCGHSA enrichment
  14. 2026-08-17 19:15 UTCEG score recompute
  15. 2026-08-17 19:15 UTCGHSA enrichment
  16. 2026-08-17 13:47 UTCEPSS rescore
  17. 2026-08-17 06:27 UTCEG score recompute
  18. 2026-08-17 06:27 UTCGHSA enrichment
  19. 2026-08-17 05:57 UTCEG score recompute▲ 7.50
  20. 2026-08-17 05:57 UTCGHSA enrichment
  21. 2026-08-17 05:54 UTCMITRE cvelistV5CVSS v3 → 7.5 · severity → HIGH
  22. 2026-08-17 05:28 UTCEG score recompute
  23. 2026-08-17 05:28 UTCGHSA enrichment
  24. 2026-08-17 05:24 UTCMITRE cvelistV5
  25. 2026-08-16 14:56 UTCEPSS rescore
Show 5 more
  1. 2026-08-16 14:56 UTCEPSS rescore
  2. 2026-08-16 02:15 UTCEPSS rescore
  3. 2026-08-15 06:23 UTCNVD update
  4. 2026-08-15 06:17 UTCEG score recompute
  5. 2026-08-15 06:12 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-72502?
CVE-2026-72502 is a high vulnerability published on August 15, 2026. In the Linux kernel, the following vulnerability has been resolved: tcp: ipv6: clamp default adverting MSS to avoid GSOBYFRAGS (0xFFFF) When MTU is large, ip6defaultadvmss() can return IPV6_MAXPLEN (65535). This is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535. However, 0xFFFF is…
When was CVE-2026-72502 disclosed?
CVE-2026-72502 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-2026-72502 actively exploited?
CVE-2026-72502 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 50.2% of all scored CVEs.
What is the CVSS score of CVE-2026-72502?
CVE-2026-72502 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-72502?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-72502, 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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