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CVE-2021-47294

netrom: Decrease sock refcount when sock timers expire

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.4.277, 4.9.277, 4.14.241, 4.19.199, 3.19, and 1 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From 4.4.173 · fixed in 4.4.277; From 4.9.155 · fixed in 4.9.277; From 4.14.98 · fixed in 4.14.241; From 4.19.20 · fixed in 4.19.199; From 3.18.134 · fixed in 3.19; From 4.20.7 · fixed in 4.21

  • Linux Linux

    5.0

References 8

git.kernel.org