7.5
HIGH
CVSS 3.1
CVE-2026-72502
tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)
Overview
Description
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".
Details
INFO
Published Date :
Aug. 15, 2026, 6:22 a.m.
Last Modified :
Aug. 17, 2026, 6:19 a.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
Clamp default advertised MSS to prevent NULL pointer dereference due to GSO_BY_FRAGS.
- Update the Linux kernel to resolve the vulnerability.
- Apply the patch that clamps default advertised MSS.
- Ensure tcp and ipv6 configurations are updated.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-72502.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-72502 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-72502
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-72502 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-72502 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '560b33b434e922ef97f9ff23aa2e909ef7aacd5c', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '21f69ac1879bb970588d5e7c12a96e6542f7c1a7', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'c0db3dc2ac323b6c4b76adede3b355a9daa6dea8', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '572fff10819dfc359298d1f774839e76a4d96f93', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '8e6214a530c03e341dc1b0a846c8f2b716b3551a', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'd774cdbda6634a78d0f2baf201ee5a8c57f3bc0e', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'a210791f33345aa87187f7d7a9f3b9b7f4a28e6d', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22', 'versionType': 'git'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.8'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.8', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '560b33b434e922ef97f9ff23aa2e909ef7aacd5c', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '21f69ac1879bb970588d5e7c12a96e6542f7c1a7', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'c0db3dc2ac323b6c4b76adede3b355a9daa6dea8', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '572fff10819dfc359298d1f774839e76a4d96f93', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '8e6214a530c03e341dc1b0a846c8f2b716b3551a', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'd774cdbda6634a78d0f2baf201ee5a8c57f3bc0e', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'a210791f33345aa87187f7d7a9f3b9b7f4a28e6d', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22', 'versionType': 'git'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.8'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.8', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'affected'}] -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 15, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '560b33b434e922ef97f9ff23aa2e909ef7aacd5c', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '21f69ac1879bb970588d5e7c12a96e6542f7c1a7', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'c0db3dc2ac323b6c4b76adede3b355a9daa6dea8', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '572fff10819dfc359298d1f774839e76a4d96f93', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '8e6214a530c03e341dc1b0a846c8f2b716b3551a', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'd774cdbda6634a78d0f2baf201ee5a8c57f3bc0e', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': 'a210791f33345aa87187f7d7a9f3b9b7f4a28e6d', 'versionType': 'git'}, {'status': 'affected', 'version': '3953c46c3ac7eef31a9935427371c6f54a22f1ba', 'lessThan': '2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22', 'versionType': 'git'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '4.8'}, {'status': 'unaffected', 'version': '0', 'lessThan': '4.8', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '5.10.261', 'versionType': 'semver', 'lessThanOrEqual': '5.10.*'}, {'status': 'unaffected', 'version': '5.15.212', 'versionType': 'semver', 'lessThanOrEqual': '5.15.*'}, {'status': 'unaffected', 'version': '6.1.178', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.145', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.97', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.40', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.5', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'affected'}] Added Description 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". Added Reference https://git.kernel.org/stable/c/21f69ac1879bb970588d5e7c12a96e6542f7c1a7 Added Reference https://git.kernel.org/stable/c/2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22 Added Reference https://git.kernel.org/stable/c/560b33b434e922ef97f9ff23aa2e909ef7aacd5c Added Reference https://git.kernel.org/stable/c/572fff10819dfc359298d1f774839e76a4d96f93 Added Reference https://git.kernel.org/stable/c/8e6214a530c03e341dc1b0a846c8f2b716b3551a Added Reference https://git.kernel.org/stable/c/a210791f33345aa87187f7d7a9f3b9b7f4a28e6d Added Reference https://git.kernel.org/stable/c/c0db3dc2ac323b6c4b76adede3b355a9daa6dea8 Added Reference https://git.kernel.org/stable/c/d774cdbda6634a78d0f2baf201ee5a8c57f3bc0e
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.