CVE-2026-89555

CVE CVE-2026-89555EUVD EUVD-2026-76466Published 2026-09-11T19:44:28.000ZLast changed 2026-09-14T12:00:57.000ZCVSS 9.8

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: mpls: reload header after pskb_may_pull() mpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop when an MPLS route has multiple nexthops. While walking the MPLS label stack, the hash routine caches hdr for the current label. After finding the bottom-of-stack label, it calls pskb_may_pull() before reading the inner IP header. If an skb is constructed with the inner IP header in nonlinear data and insufficient tailroom in the linear head, pskb_may_pull() calls pskb_expand_head() to replace the skb head and free the old one. This leaves hdr pointing to freed memory. The IPv6 path can invalidate hdr again when it performs a second pull for the larger header. The issue was found through static analysis. A reproducer sending a legal Geneve packet through a bareudp/MPLS multipath setup triggered the same KASAN report in 2 of 2 unpatched runs: BUG: KASAN: slab-use-after-free in mpls_select_multipath Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23 Call Trace: mpls_select_multipath mpls_forward __netif_receive_skb_list_core netif_receive_skb_list_internal napi_complete_done gro_cell_poll __napi_poll net_rx_action Freed by task 23: kfree pskb_expand_head __pskb_pull_tail mpls_select_multipath Reload hdr from the current skb head after each successful pull before deriving the inner IPv4 or IPv6 header pointer.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

Linux — Linux 9f427a0e474a67b454420c131709600d44850486 <aa4fe0b450a461aa1162fe8375f5d28f4c957df8; 4.10; patch: 5.10.270; 9f427a0e474a67b454420c131709600d44850486 <d9640239827d6d0cb84263b590f7a4f1596c17eb; patch: 7.3-rc1; patch: 6.1.188; 9f427a0e474a67b454420c131709600d44850486 <bfaaff99238326166694354a63a76c02563f98b1; patch: 6.12.109; patch: 0; 9f427a0e474a67b454420c131709600d44850486 <fed638a248116b8a249bd4202d28e5934bdc65ad; patch: 7.2.4; ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb; 9f427a0e474a67b454420c131709600d44850486 <b1c0783b2facc398437ad8f8b86c636d7a78f8db; 9f427a0e474a67b454420c131709600d44850486 <49d38c1b4390412f8950d33dfaee0ccbd17beb81; 9f427a0e474a67b454420c131709600d44850486 <d82b90a38c2ca8a0694428eab0e9551c23f2447d; patch: 6.6.157; 4.9.8 <4.10; patch: 6.18.50; 9f427a0e474a67b454420c131709600d44850486 <29e63b8d9fc150cc191b1c6eb7e16e1247e1b650; patch: 5.15.221

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

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Linux — Linux

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