{"cve":"CVE-2026-89555","nvd":{"published":"2026-09-11T20:19:39.147","modified":"2026-10-19T09:17:50.940","status":"Received","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.","cvss_v4":null,"cvss_v3":{"version":"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},"cwes":[],"references":["https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650","https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81","https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8","https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db","https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-89555","score":0.00694,"percentile":0.52663,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}