netrom: Decrease sock refcount when sock timers expire
Priority LOW 25CWE-672Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
In the Linux kernel, the following vulnerability has been resolved: netrom: Decrease sock refcount when sock timers expire Commit 63346650c1a9 ("netrom: switch to sock timer API") switched to use sock timer API. It replaces mod_timer() by sk_reset_timer(), and del_timer() by sk_stop_timer(). Function sk_reset_timer() will increase the refcount of sock if it is called on an inactive timer, hence, in case the timer expires, we need to decrease the refcount ourselves in the handler, otherwise, the sock refcount will be unbalanced and the sock will never be freed.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00276 20th percentileScored 2026-11-07
Fix Fixed Linux (Linux): 4.4.277, 4.9.277, 4.14.241 +7
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 | 4.4.173 to before 4.4.277; 4.9.155 to before 4.9.277; 4.14.98 to before 4.14.241; 4.19.20 to before 4.19.199; 3.18.134 to before 3.19; 4.20.7 to before 4.21 | 4.4.277, 4.9.277, 4.14.241, 4.19.199, 3.19, 4.21 | Patch available | CNA |
| Linux | Linux | 5.0 and later | 4.4.277, 4.9.277, 4.14.241, 4.19.199, 5.4.136, 5.10.54, 5.13.6, 5.14 | Patch available | CNA |
- Linux VendorLinux Affected 4.4.173 to before 4.4.277; 4.9.155 to before 4.9.277; 4.14.98 to before 4.14.241; 4.19.20 to before 4.19.199; 3.18.134 to before 3.19; 4.20.7 to before 4.21 Fixed in 4.4.277, 4.9.277, 4.14.241, 4.19.199, 3.19, 4.21 Patch available CNA
- Linux VendorLinux Affected 5.0 and later Fixed in 4.4.277, 4.9.277, 4.14.241, 4.19.199, 5.4.136, 5.10.54, 5.13.6, 5.14 Patch available CNA
CPE configurations NVD · 5
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.4.173 to before 4.4.277; 4.9.155 to before 4.9.277; 4.14.98 to before 4.14.241; 4.19.20 to before 4.19.199; 5.0 to before 5.4.136; 5.5 to before 5.10.54; 5.11 to before 5.13.6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:3.18.134:*:*:*:*:*:*:* | 3.18.134 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:4.20.7:*:*:*:*:*:*:* | 4.20.7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.14:rc1:*:*:*:*:*:* | 5.14 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.14:rc2:*:*:*:*:*:* | 5.14 rc2 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.4.173 to before 4.4.277; 4.9.155 to before 4.9.277; 4.14.98 to before 4.14.241; 4.19.20 to before 4.19.199; 5.0 to before 5.4.136; 5.5 to before 5.10.54; 5.11 to before 5.13.6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:3.18.134:*:*:*:*:*:*:* Versions 3.18.134 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:4.20.7:*:*:*:*:*:*:* Versions 4.20.7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.14:rc1:*:*:*:*:*:* Versions 5.14 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.14:rc2:*:*:*:*:*:* Versions 5.14 rc2 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.4.277, 4.9.277, 4.14.241, 4.19.199, 3.19, 4.21
- Fix · CNA Linux (Linux) Fixed in 4.4.277, 4.9.277, 4.14.241, 4.19.199, 5.4.136, 5.10.54, 5.13.6, 5.14
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-47294
- 2026-10-03 Alias added: GHSA-wc9c-rv2v-442r
References
Patch 8
- https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29
- https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf
- https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef
- https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950
- https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3
- https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a
- https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250
- https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8
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- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2021-47294 · CVE Program
- CVE-2021-47294 · NVD
- FIRST EPSS
- GHSA-wc9c-rv2v-442r · GitHub Advisory Database · CC BY 4.0
- CVE-2021-47294 · Red Hat security data · CC BY 4.0
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