CVE-2021-47294

netrom: Decrease sock refcount when sock timers expire

MEDIUM
5.5
CVSS Score
Published: May 21, 2024 at 02:35 PM UTC
Updated: June 17, 2026 at 04:17 AM UTC
1 product affected across 1 vendorLinux Kernel

Using Linux by Linux?

Get instant alerts when new vulnerabilities affect Linux - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM5.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≥ 3.18.134v ≥ 4.20.73.18.134 ≤ v < 3.194.14.98 ≤ v < 4.14.2414.19.20 ≤ v < 4.19.1994.20.7 ≤ v < 4.214.4.173 ≤ v < 4.4.2774.9.155 ≤ v < 4.9.2775.0 ≤ v < 5.10.545.0 ≤ v < 5.13.65.0 ≤ v < 5.145.0 ≤ v < 5.4.1365.11 ≤ v < 5.13.65.5 ≤ v < 5.10.540adf571fa34b27bd0b97b408cc0f0dc54b72f0eb2c6b572458a9127e8070df13fa7f115c29ab1d923.18.1344.14.984.19.204.20.74.4.1734.9.1555.14 rc15.14 rc2519e8a22a454b1f1baa3a151b184fe51bc18e17863346650c1a94a92be61a57416ac88c0a47c4327baa9e32336bf6d0d74a7c3486d2a27feaf57cd5fce29e8a259de767f7210d346ad2b031cb8ab2732f1d9a1f2ef6ff17293d21d5e6b80e04bea0cf508
Vendor states this is fixed in 25df44e90ff5959b5c24ad361b648504a7e39ef3 (fixed)
Vendor states this is fixed in 48866fd5c361ea417ed24b43fc2a7dc2f5b060ef (fixed)
Vendor states this is fixed in 517a16b1a88bdb6b530f48d5d153478b2552d9a8 (fixed)
Vendor states this is fixed in 6811744bd0efb9e472cb15d066cdb460beb8cb8a (fixed)
Vendor states this is fixed in 853262355518cd1247515b74e83fabf038aa6c29 (fixed)
Vendor states this is fixed in 9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950 (fixed)
Vendor states this is fixed in a01634bf91f2b6c42583770eb6815fb6d1e251cf (fixed)
Vendor states this is fixed in bc1660206c3723c37ed4d622ad81781f1e987250 (fixed)
Affected range stops below 3.19, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 4.14.241 (unaffected)
Vendor states this is fixed in 4.19.199 (unaffected)
Affected range stops below 4.21, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 4.4.277 (unaffected)
Vendor states this is fixed in 4.9.277 (unaffected)
Vendor states this is fixed in 5.0 (unaffected)
Vendor states this is fixed in 5.10.54 (unaffected)
Vendor states this is fixed in 5.13.6 (unaffected)
Vendor states this is fixed in 5.14 (unaffected)
Vendor states this is fixed in 5.4.136 (unaffected)

References (8)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/25df44e90ff5959b5c24ad361b648504a7e39ef3
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/48866fd5c361ea417ed24b43fc2a7dc2f5b060ef
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/517a16b1a88bdb6b530f48d5d153478b2552d9a8
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/6811744bd0efb9e472cb15d066cdb460beb8cb8a
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/853262355518cd1247515b74e83fabf038aa6c29
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/9619cc7d97c3aa8ed3cfd2b8678b74fb6d6c7950
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/a01634bf91f2b6c42583770eb6815fb6d1e251cf
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/bc1660206c3723c37ed4d622ad81781f1e987250

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-672

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card