{"id":"CVE-2026-99041","revision":"1fc7ce1cc52949b58fe3d8376202fe21","records":[{"revision":"1fc7ce1cc52949b58fe3d8376202fe21","observedAt":"2026-10-23T16:01:20.601+00:00","statement":{"source":"cve-program","id":"CVE-2026-99041","aliases":[],"title":"ip6_gre: remove obsolete ERSPAN PMTU update","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nip6_gre: remove obsolete ERSPAN PMTU update\n\nA tc tunnel_key action can attach a METADATA_IP_TUNNEL dst to an skb,\nand mirred can redirect it to a native ip6erspan device. The legacy PMTU\nupdate in ip6erspan_tunnel_xmit() treats that metadata dst as a route.\nSince it has no output device, dst_dev(dst)->mtu dereferences NULL.\n\nOn v7.2 with KASAN, an initial UID/GID 65534 process with CapEff 0 used\nself-created user and network namespaces to trigger:\n\n  KASAN: null-ptr-deref\n  RIP: ip6erspan_tunnel_xmit+0x10fc/0x2cc0\n  Kernel panic - not syncing: Fatal exception in interrupt\n\nThe update is obsolete. Commit fe1a4ca0a2b7 (\"ip6_gre: process toobig\nin a better way\") changed IPv6 GRE Too Big handling to update the\nunderlay route and removed the equivalent block from __gre6_xmit().\nip6_tnl_xmit() then propagates the underlay PMTU to the overlay route.\n\nRemove the stale ERSPAN copy and its now-unused dst variable. This\neliminates the metadata-dst dereference and keeps ERSPAN aligned with\nIPv6 GRE PMTU handling.","state":0,"publishedAt":"2026-10-23T12:22:00.403+00:00","modifiedAt":"2026-10-23T12:22:00.403+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/ip6_gre.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"5a963eb61b7c39e6c422b6e48619d19d04719358\",\n                            \"lessThan\": \"b14a682ad7d45345701e08f9279d483a1da8b36c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5a963eb61b7c39e6c422b6e48619d19d04719358\",\n                            \"lessThan\": \"f5b143f4cd3fb7673df8d727550478a4b762908a\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5a963eb61b7c39e6c422b6e48619d19d04719358\",\n                            \"lessThan\": \"2d06cb25a497d3a7034ef9d172626c2d6620a0f1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5a963eb61b7c39e6c422b6e48619d19d04719358\",\n                            \"lessThan\": \"8f27260b989f488760289276377db24fbfb20bfa\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"5a963eb61b7c39e6c422b6e48619d19d04719358\",\n                            \"lessThan\": \"8bc60db48e8cba35488bbd6e1f94aa990afa275a\",\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/ip6_gre.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.16\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.16\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.160\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.114\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.58\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.11\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/b14a682ad7d45345701e08f9279d483a1da8b36c","https://git.kernel.org/stable/c/f5b143f4cd3fb7673df8d727550478a4b762908a","https://git.kernel.org/stable/c/2d06cb25a497d3a7034ef9d172626c2d6620a0f1","https://git.kernel.org/stable/c/8f27260b989f488760289276377db24fbfb20bfa","https://git.kernel.org/stable/c/8bc60db48e8cba35488bbd6e1f94aa990afa275a"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99041","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-99041","identifiers":["CVE-2026-99041"]},"retained":false,"historicalAffected":[]}],"coverage":[]}