CVE-2026-89555mpls: reload header after pskb_may_pull()
- 9.8CriticalCVSS base score
- 0.69%Exploitation in 30 daysEPSS · top 47% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By Linux
Published
- 38 days later
· 38 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.69% · top 47% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.8.
Affected products
- affected 9f427a0e474a67b454420c131709600d44850486 – < aa4fe0b450a461aa1162fe8375f5d28f4c957df8
- affected 9f427a0e474a67b454420c131709600d44850486 – < b1c0783b2facc398437ad8f8b86c636d7a78f8db
- affected 9f427a0e474a67b454420c131709600d44850486 – < bfaaff99238326166694354a63a76c02563f98b1
- affected 9f427a0e474a67b454420c131709600d44850486 – < d9640239827d6d0cb84263b590f7a4f1596c17eb
- affected 9f427a0e474a67b454420c131709600d44850486 – < fed638a248116b8a249bd4202d28e5934bdc65ad
- affected 9f427a0e474a67b454420c131709600d44850486 – < d82b90a38c2ca8a0694428eab0e9551c23f2447d
- affected 9f427a0e474a67b454420c131709600d44850486 – < 49d38c1b4390412f8950d33dfaee0ccbd17beb81
- affected 9f427a0e474a67b454420c131709600d44850486 – < 29e63b8d9fc150cc191b1c6eb7e16e1247e1b650
- affected ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb
- affected 4.9.8 – < 4.10
- affected 4.10
- unaffected < 4.10
- unaffected 5.10.270 – ≤ 5.10.*
- unaffected 5.15.221 – ≤ 5.15.*
- unaffected 6.1.188 – ≤ 6.1.*
- unaffected 6.6.157 – ≤ 6.6.*
- unaffected 6.12.109 – ≤ 6.12.*
- unaffected 6.18.50 – ≤ 6.18.*
- unaffected 7.2.4 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8 (opens in a new tab)
- https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db (opens in a new tab)
- https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1 (opens in a new tab)
- https://git.kernel.org/stable/c/d9640239827d6d0cb84263b590f7a4f1596c17eb (opens in a new tab)
- https://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad (opens in a new tab)
- https://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d (opens in a new tab)
- https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81 (opens in a new tab)
- https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-76466 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-89555)Record last updated .