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CVE-2026-98261

Linux: cifs: Fix server use-after-free in cifs_chan_skip_or_disable()

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
8.1High
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.44%Chance of exploitation activity in the next 30 days, higher than 37% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in0338489960ddad6368bce55e8adbc176c523093dAlso 7a1b27780b113583a94256d58dabfe7c0d9286e7, 717e0a25036b6c92cecace30913b2d874a4c22b8 and 2 moreCVE List
Published6 Oct 2026Updated 19 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

Description

In the Linux kernel, the following vulnerability has been resolved:

cifs: Fix server use-after-free in cifs_chan_skip_or_disable()

When a secondary channel is no longer supported by the server, cifs_chan_skip_or_disable() drops the channel reference with cifs_put_tcp_session() and then continues to use the server pointer by calling cifs_signal_cifsd_for_reconnect() on it and reading its primary_server pointer. cifs_put_tcp_session() can drop the last reference of the channel and tear it down, so both the channel and the primary server (whose reference is also dropped by cifs_put_tcp_session()) can be freed before they are signaled for reconnect.

Signal the channel and the primary server and capture the primary server pointer before dropping the channel reference with cifs_put_tcp_session().

Text from CVE List

Affected versions 15

  • Linuxaffected: 50e8363ecc85da49764781da90ebffe1a657b370 before 0338489960ddad6368bce55e8adbc176c523093dCVE List
  • Linuxaffected: f591062bdbf4742b7f1622173017f19e927057b0 before edd52eae5fcfb8433b6bb0e7cd98db438fe01227CVE List
  • Linuxaffected: f591062bdbf4742b7f1622173017f19e927057b0 before fcc0a935bb6e37ecbf7e4335061309f896f35780CVE List
  • Linuxaffected: f591062bdbf4742b7f1622173017f19e927057b0 before 7a1b27780b113583a94256d58dabfe7c0d9286e7CVE List
  • Linuxaffected: f591062bdbf4742b7f1622173017f19e927057b0 before 717e0a25036b6c92cecace30913b2d874a4c22b8CVE List
  • Linuxaffected: d61ba1d71ea6039eca7ada870bf3f0c3c8fc12e4CVE List
  • Linuxaffected: 6.6.15 before 6.6.158CVE List
  • Linuxaffected: 6.7.3 before 6.8CVE List
  • Linuxaffected: 6.8CVE List
  • Linuxunaffected: all versions before 6.8CVE List
  • Linuxunaffected: 6.6.158 through 6.6.*CVE List
  • Linuxunaffected: 6.12.112 through 6.12.*CVE List
  • Linuxunaffected: 6.18.54 through 6.18.*CVE List
  • Linuxunaffected: 7.2.8 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 5