CVE-2026-89555mpls: reload header after pskb_may_pull()
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 9.8 CRITICAL (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 9f427a0e474a67b454420c131709600d44850486 before aa4fe0b450a461aa1162fe8375f5d28f4c957df8; from 9f427a0e474a67b454420c131709600d44850486 before b1c0783b2facc398437ad8f8b86c636d7a78f8db; from 9f427a0e474a67b454420c131709600d44850486 before bfaaff99238326166694354a63a76c02563f98b1; from 9f427a0e474a67b454420c131709600d44850486 before d9640239827d6d0cb84263b590f7a4f1596c17eb; from 9f427a0e474a67b454420c131709600d44850486 before fed638a248116b8a249bd4202d28e5934bdc65ad; from 9f427a0e474a67b454420c131709600d44850486 before d82b90a38c2ca8a0694428eab0e9551c23f2447d; from 9f427a0e474a67b454420c131709600d44850486 before 49d38c1b4390412f8950d33dfaee0ccbd17beb81; from 9f427a0e474a67b454420c131709600d44850486 before 29e63b8d9fc150cc191b1c6eb7e16e1247e1b650; and 2 more ranges | CNA record |
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
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.