mm/damon/sysfs: fix use-after-free in state_show()
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: mm/damon/sysfs: fix use-after-free in state_show() state_show() reads kdamond->damon_ctx without holding damon_sysfs_lock. This allows a use-after-free race: CPU 0 CPU 1 ----- ----- state_show() damon_sysfs_turn_damon_on() ctx = kdamond->damon_ctx; mutex_lock(&damon_sysfs_lock); damon_destroy_ctx(kdamond->damon_ctx); kdamond->damon_ctx = NULL; mutex_unlock(&damon_sysfs_lock); damon_is_running(ctx); /* ctx is freed */ mutex_lock(&ctx->kdamond_lock); /* UAF */ (The race can also occur with damon_sysfs_kdamonds_rm_dirs() and damon_sysfs_kdamond_release(), which free or replace the context under damon_sysfs_lock.) Fix by taking damon_sysfs_lock before dereferencing the context, mirroring the locking used in pid_show(). The bug has existed since state_show() first accessed kdamond->damon_ctx.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.18 and later | 6.1.153, 6.6.107, 6.12.48, 6.16.8, 6.17 | Patch available | CNA |
- Linux VendorLinux Affected 5.18 and later Fixed in 6.1.153, 6.6.107, 6.12.48, 6.16.8, 6.17 Patch available CNA
CPE configurations NVD · 7
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.18 to before 6.1.153; 6.2 to before 6.6.107; 6.7 to before 6.12.48; 6.13 to before 6.16.8 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* | 6.17 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* | 6.17 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* | 6.17 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* | 6.17 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* | 6.17 rc5 | Vulnerable | Linux |
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | 11.0 | Vulnerable | Debian |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.18 to before 6.1.153; 6.2 to before 6.6.107; 6.7 to before 6.12.48; 6.13 to before 6.16.8 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* Versions 6.17 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* Versions 6.17 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* Versions 6.17 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* Versions 6.17 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* Versions 6.17 rc5 Vulnerable ·Linux
- cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* Versions 11.0 Vulnerable ·Debian
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.153, 6.6.107, 6.12.48, 6.16.8, 6.17
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2025-39877
- 2026-10-03 Alias added: GHSA-46f8-9r54-mw7h
- 2026-11-05 CISA SSVC decision points changed
References
Patch 5
- https://git.kernel.org/stable/c/3858c44341ad49dc7544b19cc9f9ecffaa7cc50e
- https://git.kernel.org/stable/c/60d7a3d2b985a395318faa1d88da6915fad11c19
- https://git.kernel.org/stable/c/26d29b2ac87a2989071755f9828ebf839b560d4c
- https://git.kernel.org/stable/c/4e87f461d61959647464a94d11ae15c011be58ce
- https://git.kernel.org/stable/c/3260a3f0828e06f5f13fac69fb1999a6d60d9cff
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Sources
- CVE-2025-39877 · CVE Program
- CVE-2025-39877 · NVD
- FIRST EPSS
- GHSA-46f8-9r54-mw7h · GitHub Advisory Database · CC BY 4.0
- CVE-2025-39877 · Red Hat security data · CC BY 4.0
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