{"id":"CVE-2026-72502","revision":"ec1604f0561b40488db3208cab95be5e","records":[{"revision":"ec1604f0561b40488db3208cab95be5e","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-72502","aliases":[],"title":"tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)\n\nWhen MTU is large, ip6_default_advmss() can return IPV6_MAXPLEN (65535).\nThis is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535.\n\nHowever, 0xFFFF is also used as a magic value GSO_BY_FRAGS in the kernel.\nIf a TCP packet with gso_size=0xFFFF is passed to skb_segment(), it will\nbe mistakenly treated as GSO_BY_FRAGS, leading to a NULL pointer\ndereference because local TCP packets do not use frag_list.\n\nFix this by returning min(IPV6_MAXPLEN, GSO_BY_FRAGS - 1) (65534) from\nip6_default_advmss() when MTU is large.\n\nAlso update the stale comment in ip6_default_advmss() which suggested\nthat IPV6_MAXPLEN is returned to mean \"any MSS\".","state":0,"publishedAt":"2026-08-15T05:57:33.647+00:00","modifiedAt":"2026-10-16T18:55:27.761+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv6/route.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"560b33b434e922ef97f9ff23aa2e909ef7aacd5c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"21f69ac1879bb970588d5e7c12a96e6542f7c1a7\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"c0db3dc2ac323b6c4b76adede3b355a9daa6dea8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"572fff10819dfc359298d1f774839e76a4d96f93\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"8e6214a530c03e341dc1b0a846c8f2b716b3551a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"d774cdbda6634a78d0f2baf201ee5a8c57f3bc0e\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"a210791f33345aa87187f7d7a9f3b9b7f4a28e6d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"3953c46c3ac7eef31a9935427371c6f54a22f1ba\",\n                            \"lessThan\": \"2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/ipv6/route.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.8\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.8\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.261\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.212\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.178\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.145\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.97\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.40\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.1.5\",\n                            \"lessThanOrEqual\": \"7.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/560b33b434e922ef97f9ff23aa2e909ef7aacd5c","https://git.kernel.org/stable/c/21f69ac1879bb970588d5e7c12a96e6542f7c1a7","https://git.kernel.org/stable/c/c0db3dc2ac323b6c4b76adede3b355a9daa6dea8","https://git.kernel.org/stable/c/572fff10819dfc359298d1f774839e76a4d96f93","https://git.kernel.org/stable/c/8e6214a530c03e341dc1b0a846c8f2b716b3551a","https://git.kernel.org/stable/c/d774cdbda6634a78d0f2baf201ee5a8c57f3bc0e","https://git.kernel.org/stable/c/a210791f33345aa87187f7d7a9f3b9b7f4a28e6d","https://git.kernel.org/stable/c/2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72502","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-72502","identifiers":["CVE-2026-72502"]},"retained":false,"historicalAffected":[]}],"coverage":[]}