Answer in brief
CVE-2026-89555 records a Critical severity (CVSS 9.8) vulnerability in mpls: reload header after pskb_may_pull(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=9f427a0e474a67b454420c131709600d44850486 <fed638a248116b8a249bd4202d28e5934bdc65ad || >=9f427a0e474a67b454420c131709600d44850486 <d82b90a38c2ca8a0694428eab0e9551c23f2447d || >=9f427a0e474a67b454420c131709600d44850486 <49d38c1b4390412f8950d33dfaee0ccbd17beb81 || >=9f427a0e474a67b454420c131709600d44850486 <29e63b8d9fc150cc191b1c6eb7e16e1247e1b650 || ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb || >=4.9.8 <4.10 | fed638a248116b8a249bd4202d28e5934bdc65ad, d82b90a38c2ca8a0694428eab0e9551c23f2447d, 49d38c1b4390412f8950d33dfaee0ccbd17beb81, 29e63b8d9fc150cc191b1c6eb7e16e1247e1b650, 4.10 |
| Linux/Linuxgeneric | 4.10 | Not reported |
| Linux/Linuxgeneric | >=9f427a0e474a67b454420c131709600d44850486 <aa4fe0b450a461aa1162fe8375f5d28f4c957df8 || >=9f427a0e474a67b454420c131709600d44850486 <b1c0783b2facc398437ad8f8b86c636d7a78f8db || >=9f427a0e474a67b454420c131709600d44850486 <bfaaff99238326166694354a63a76c02563f98b1 || >=9f427a0e474a67b454420c131709600d44850486 <d9640239827d6d0cb84263b590f7a4f1596c17eb || >=9f427a0e474a67b454420c131709600d44850486 <fed638a248116b8a249bd4202d28e5934bdc65ad || >=9f427a0e474a67b454420c131709600d44850486 <d82b90a38c2ca8a0694428eab0e9551c23f2447d || >=9f427a0e474a67b454420c131709600d44850486 <49d38c1b4390412f8950d33dfaee0ccbd17beb81 || >=9f427a0e474a67b454420c131709600d44850486 <29e63b8d9fc150cc191b1c6eb7e16e1247e1b650 || ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb || >=4.9.8 <4.10 | aa4fe0b450a461aa1162fe8375f5d28f4c957df8, b1c0783b2facc398437ad8f8b86c636d7a78f8db, bfaaff99238326166694354a63a76c02563f98b1, d9640239827d6d0cb84263b590f7a4f1596c17eb, fed638a248116b8a249bd4202d28e5934bdc65ad, d82b90a38c2ca8a0694428eab0e9551c23f2447d, 49d38c1b4390412f8950d33dfaee0ccbd17beb81, 29e63b8d9fc150cc191b1c6eb7e16e1247e1b650, 4.10 |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 11, 2026
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.
Quoted source text, attributed separately from HOL analysis.