{"id":"CVE-2026-89555","revision":"8ec8508b5125438eb0258d7a5bf1ee94","records":[{"revision":"8ec8508b5125438eb0258d7a5bf1ee94","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-89555","aliases":[],"title":"mpls: reload header after pskb_may_pull()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmpls: reload header after pskb_may_pull()\n\nmpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop\nwhen an MPLS route has multiple nexthops.  While walking the MPLS label\nstack, the hash routine caches hdr for the current label.  After finding\nthe bottom-of-stack label, it calls pskb_may_pull() before reading the\ninner IP header.\n\nIf an skb is constructed with the inner IP header in nonlinear data and\ninsufficient tailroom in the linear head, pskb_may_pull() calls\npskb_expand_head() to replace the skb head and free the old one.  This\nleaves hdr pointing to freed memory.  The IPv6 path can invalidate hdr\nagain when it performs a second pull for the larger header.\n\nThe issue was found through static analysis.  A reproducer sending a legal\nGeneve packet through a bareudp/MPLS multipath setup triggered the same\nKASAN report in 2 of 2 unpatched runs:\n\n  BUG: KASAN: slab-use-after-free in mpls_select_multipath\n  Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23\n\n  Call Trace:\n   mpls_select_multipath\n   mpls_forward\n   __netif_receive_skb_list_core\n   netif_receive_skb_list_internal\n   napi_complete_done\n   gro_cell_poll\n   __napi_poll\n   net_rx_action\n\n  Freed by task 23:\n   kfree\n   pskb_expand_head\n   __pskb_pull_tail\n   mpls_select_multipath\n\nReload hdr from the current skb head after each successful pull before\nderiving the inner IPv4 or IPv6 header pointer.","state":0,"publishedAt":"2026-09-11T19:44:28.331+00:00","modifiedAt":"2026-10-19T08:48:48.093+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/mpls/af_mpls.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"aa4fe0b450a461aa1162fe8375f5d28f4c957df8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"b1c0783b2facc398437ad8f8b86c636d7a78f8db\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"bfaaff99238326166694354a63a76c02563f98b1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"d9640239827d6d0cb84263b590f7a4f1596c17eb\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"fed638a248116b8a249bd4202d28e5934bdc65ad\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"d82b90a38c2ca8a0694428eab0e9551c23f2447d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"49d38c1b4390412f8950d33dfaee0ccbd17beb81\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"9f427a0e474a67b454420c131709600d44850486\",\n                            \"lessThan\": \"29e63b8d9fc150cc191b1c6eb7e16e1247e1b650\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"4.9.8\",\n                            \"lessThan\": \"4.10\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"semver\"\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/mpls/af_mpls.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.10\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.10\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.109\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.50\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.4\",\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":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8","https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db","https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1","https://git.kernel.org/stable/c/d9640239827d6d0cb84263b590f7a4f1596c17eb","https://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad","https://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d","https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81","https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89555","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-89555","identifiers":["CVE-2026-89555"]},"retained":false,"historicalAffected":[]}],"coverage":[]}