9.8

CVE-2026-89555: linux

CVSS: 9.8v3.1CriticalReceived
AliasesUBUNTU-CVE-2026-89555DEBIAN-CVE-2026-89555
Published 11-09-2026Last modified 19-10-2026
Open JSON

Vulnerability summary

CVE-2026-89555 is a critical (CVSS 9.8) vulnerability in linux. EPSS estimates a 0.69% chance of exploitation in the next 30 days, higher than 52.3% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.69%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 1
MGASA-2026-0506OPENSUSE-SU-2026:11880-1

Timeline

  1. 11-09-2026
    PublishedVulnerability first disclosed.
  2. 19-10-2026
    Last modifiedVulnerability information updated.

Description

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 metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.69%

Chance of exploitation in the next 30 days

Percentile

52%

Versus all other CVEs

30-day change

+0.01 pp

From 0.68% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.69%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu168 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linuxAll versions (No fix recorded) | < 6.1.190-1 | < 6.12.111-1 | < 7.2.6-1
  • linux-6.12< 6.12.111-1~deb12u1
Linux1 product
  • linux≥ 9f427a0e474a67b454420c131709600d44850486, < aa4fe0b450a461aa1162fe8375f5d28f4c957df8 | ≥ 9f427a0e474a67b454420c131709600d44850486, < b1c0783b2facc398437ad8f8b86c636d7a78f8db | ≥ 9f427a0e474a67b454420c131709600d44850486, < bfaaff99238326166694354a63a76c02563f98b1 | ≥ 9f427a0e474a67b454420c131709600d44850486, < d9640239827d6d0cb84263b590f7a4f1596c17eb | ≥ 9f427a0e474a67b454420c131709600d44850486, < fed638a248116b8a249bd4202d28e5934bdc65ad | ≥ 9f427a0e474a67b454420c131709600d44850486, < d82b90a38c2ca8a0694428eab0e9551c23f2447d | ≥ 9f427a0e474a67b454420c131709600d44850486, < 49d38c1b4390412f8950d33dfaee0ccbd17beb81 | ≥ 9f427a0e474a67b454420c131709600d44850486, < 29e63b8d9fc150cc191b1c6eb7e16e1247e1b650 | ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb | ≥ 4.9.8, < 4.10 | 4.10

3 vendors · 171 products

References

13 links
Show all 13 references