net/x25: fix use-after-free in x25_kill_by_neigh()
In the Linux kernel, the following vulnerability has been resolved: net/x25: fix use-after-free in x25_kill_by_neigh() x25_kill_by_neigh() walks the global X.25 socket list looking for sockets attached to a terminating neighbour. x25_list_lock protects list membership while the lookup is in progress, but it does not pin a socket's lifetime after the lock is dropped. The function currently drops x25_list_lock before calling lock_sock(s). A concurrent close can run x25_release(), remove the same socket from x25_list, and drop the last socket reference in that window. The neighbour teardown path can then lock or inspect a freed struct sock/struct x25_sock. Take sock_hold(s) while x25_list_lock still proves that the list entry is live, then drop the temporary reference after the socket has been locked, rechecked, and released. Recheck x25_sk(s)->neighbour after lock_sock(), because another path may have disconnected the socket before this path acquired the socket lock. Restart the list walk after each disconnect because the list lock was dropped and the previous iterator state may no longer be valid. A QEMU/KASAN run against origin/master reproduced a slab-use-after-free in x25_kill_by_neigh().
- Published
- Aug 10, 2026
- Updated
- Aug 19, 2026
- EPSS
- 0.7% · 53th percentile
- CWE
- —
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Report tools
Action score
39
Monitor
Low priority for now.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.7%
CNA vs NVD score
- NVD
- —
- CNA · Linux
- 9.8
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
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We use this product, ask for helpAffected systems
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Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- dffc859d1d9560da594e4282091781b8d2715f00, 858642789ada1b48630f322e59416ca9fca3e6b7, 4c240c5a105557e4546d0836e694868f22fd09b0, 9acf05b4e7b55fdb712ef7b331dbce5bcd391d0f, 4a279d7ee1c65411b4055ecd428b8aa2b1711c1f, 671529db75e6be777bb1c76aa07c2bdd2992be6d, 5.18affected
- 5c94b6205e87411dbe9dc1ca088eb36b8837fb47 and later · before db6b04f6d65549bb1c7bc8e64a92e7b7d03be676affected · git
- 409570a619c1cda2e0fde6018a256b9e3d3ba0ee and later · before 5e8a754ac2009a88a7b99ab61eab6296eed360f3affected · git
- 7781607938c8371d4c2b243527430241c62e39c2 and later · before c98a454d1a9e1bd09d5fd55a7aa589b199340b88affected · git
- 7781607938c8371d4c2b243527430241c62e39c2 and later · before 3f4fe26c20c30bd5a2e2583e80685def0b27858caffected · git
- 7781607938c8371d4c2b243527430241c62e39c2 and later · before 610678d4be94b619c751572e8a58de705592cd07affected · git
- 7781607938c8371d4c2b243527430241c62e39c2 and later · before ec6d91a1bf2ebd767d3d43f6d249ee0ed3f4558aaffected · git
- 7781607938c8371d4c2b243527430241c62e39c2 and later · before 9aabda553184346f74810e2ee1d96920b4612e3faffected · git
- 7781607938c8371d4c2b243527430241c62e39c2 and later · before 5499e0602d2faafd42c580d25f615903c3fbe11baffected · git
- 5.10.110 and later · before 5.10.265affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 6.1.187-1 | 6.1.187-1 |
| Debian:12 | linux-6.12 | before 6.12.101-1~deb12u1 | 6.12.101-1~deb12u1 |
| Debian:13 | linux | before 6.12.101-1 | 6.12.101-1 |
| Debian:14 | linux | before 7.1.6-1 | 7.1.6-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation40Plan
- CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment40Plan
- CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()40Plan
- CVE-2026-74309vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler40Plan
- CVE-2026-74280crypto: marvell/octeontx - fix DMA cleanup using wrong loop index40Plan
- CVE-2026-74279crypto: cavium/cpt - fix DMA cleanup using wrong loop index40Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 3f4fe26c20c30bd5a2e2583e80685def0b27858c | Vendor (CNA) |
| Linux Linux | 4.10 | Vendor (CNA) |
| Linux Linux | 4.15 | Vendor (CNA) |
| Linux Linux | 4.20 | Vendor (CNA) |
| Linux Linux | 5.10.265 | Vendor (CNA) |
| Linux Linux | 5.15.216 | Vendor (CNA) |
| Linux Linux | 5.17 | Vendor (CNA) |
| Linux Linux | 5.18 | Vendor (CNA) |
| Linux Linux | 5.5 | Vendor (CNA) |
| Linux Linux | 5499e0602d2faafd42c580d25f615903c3fbe11b | Vendor (CNA) |
| Linux Linux | 5e8a754ac2009a88a7b99ab61eab6296eed360f3 | Vendor (CNA) |
| Linux Linux | 610678d4be94b619c751572e8a58de705592cd07 | Vendor (CNA) |
| Linux Linux | 9aabda553184346f74810e2ee1d96920b4612e3f | Vendor (CNA) |
| Linux Linux | c98a454d1a9e1bd09d5fd55a7aa589b199340b88 | Vendor (CNA) |
| Linux Linux | db6b04f6d65549bb1c7bc8e64a92e7b7d03be676 | Vendor (CNA) |
| Linux Linux | ec6d91a1bf2ebd767d3d43f6d249ee0ed3f4558a | Vendor (CNA) |
| azl3 kernel 6.6.143.1-1 on Azure Linux 3.0 | 6.6.150.1-1 · CBL-Mariner Releases | Microsoft (MSRC) |
| debian:linux | 6.1.187-1 · Debian:12 | Package registry (OSV) |
| debian:linux-6.12 | 6.12.101-1~deb12u1 · Debian:12 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
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Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-26-0800 · Aug 11, 2026(Linux Kernel Güvenlik Bildirimi)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
—
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/3f4fe26c20c30bd5a2e2583e80685def0b27858c
- git.kernel.org/stable/c/5499e0602d2faafd42c580d25f615903c3fbe11b
- git.kernel.org/stable/c/5e8a754ac2009a88a7b99ab61eab6296eed360f3
- git.kernel.org/stable/c/610678d4be94b619c751572e8a58de705592cd07
- git.kernel.org/stable/c/9aabda553184346f74810e2ee1d96920b4612e3f
- git.kernel.org/stable/c/c98a454d1a9e1bd09d5fd55a7aa589b199340b88
- git.kernel.org/stable/c/db6b04f6d65549bb1c7bc8e64a92e7b7d03be676
- git.kernel.org/stable/c/ec6d91a1bf2ebd767d3d43f6d249ee0ed3f4558a
Vendor advisories and official records. Exploit/PoC links are deliberately left out.