CVE-2026-31458
Description
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0] Multiple sysfs command paths dereference contexts_arr[0] without first verifying that kdamond->contexts->nr == 1. A user can set nr_contexts to 0 via sysfs while DAMON is running, causing NULL pointer dereferences. In more detail, the issue can be triggered by privileged users like below. First, start DAMON and make contexts directory empty (kdamond->contexts->nr == 0). # damo start # cd /sys/kernel/mm/damon/admin/kdamonds/0 # echo 0 > contexts/nr_contexts Then, each of below commands will cause the NULL pointer dereference. # echo update_schemes_stats > state # echo update_schemes_tried_regions > state # echo update_schemes_tried_bytes > state # echo update_schemes_effective_quotas > state # echo update_tuned_intervals > state Guard all commands (except OFF) at the entry point of damon_sysfs_handle_cmd().
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
Linux kernel Affected 2 releases
| Version | Status | Fixed in |
|---|---|---|
| 7.0 | Affected | — |
| — | Affected | 6.6.131 |
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Fixed | 6.12.85-1 |
| sid | Fixed | 6.19.11-1 |
| forky | Fixed | 6.19.11-1 |
| bullseye | Fixed | 0 |
| bookworm | Affected | — |
References
- https://git.kernel.org/stable/c/1bfe9fb5ed2667fb075682408b776b5273162615
- https://git.kernel.org/stable/c/1e8da792672481d603fa7cd0d815577220a3ee27
- https://git.kernel.org/stable/c/708033c231bd782858f4ddbb46ee874a5a5fbdab
- https://git.kernel.org/stable/c/aba546061341b56e9ffb37e1eb661a3628b6ec12
- https://git.kernel.org/stable/c/bbe03ad3fb9e714191757ca7b41582f930be7be2
- https://www.suse.com/security/cve/CVE-2026-31458.html
- https://security-tracker.debian.org/tracker/CVE-2026-31458
CWEs
CWE-476
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.