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CVE-2026-99056

Linux: strparser: make sure __strp_recv isn't running before tearing down the parser

Linux LinuxOperating systems
Open in ThreatlineRecord JSON
CVSS
NoneNot scored
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)No scoreNo FIRST EPSS score in this snapshot yet
Fixed in9f3e9fe1b155e9b4572054d8d140586bc3512ecfAlso 0984ebc631792acf8fff105112ee74a6b8f1efccCVE List
Published23 Oct 2026Updated 23 Oct 2026CVE List

What fixes it

  • 9f3e9fe1b155e9b4572054d8d140586bc3512ecfLinuxCVE List
  • 0984ebc631792acf8fff105112ee74a6b8f1efccLinuxCVE List

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:

strparser: make sure __strp_recv isn't running before tearing down the parser

The comment above strp_done() claims that if strp is stopped, strp_recv will no longer be called. That's only true if the caller has a mechanism (eg locking) to guarantee that strp_recv() calls that started before strp_stop() have completed by the time we call strp_done().

This adds a dummy lock_sock/release_sock pair to guarantee that any in-flight strp_recv() (which runs under either bh_lock_sock or lock_sock, depending if it's called from ->sk_data_ready or strp_work) has completed.

Only espintcp can be affected by this race condition, but this patch makes sure no future user of strp can have the bug.

This could crash on strp->sk ("general mode" of strp), but this mode has been here for 9 years and has never been used. It'll be gone soon, no point worrying about it.

Switch the stopped/paused/etc bits to u8's to avoid races between strp_stop() and strp_pause/unpause().

A reproducer has been published and turns the possible UAF into an exploit [1].

Text from CVE List

Affected versions 12

  • Linuxaffected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 before a18dd388045dc7263d99a07db9de4e0f149ca8f1CVE List
  • Linuxaffected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 before 9f3e9fe1b155e9b4572054d8d140586bc3512ecfCVE List
  • Linuxaffected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 before d2b5f637b9b67a79a50d42614d10653c13b4e449CVE List
  • Linuxaffected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 before eaa3a29004c063d7e9d5ea55636f693f67e6db0fCVE List
  • Linuxaffected: e27cca96cd68fa2c6814c90f9a1cfd36bb68c593 before 0984ebc631792acf8fff105112ee74a6b8f1efccCVE List
  • Linuxaffected: 5.6CVE List
  • Linuxunaffected: all versions before 5.6CVE List
  • Linuxunaffected: 6.6.160 through 6.6.*CVE List
  • Linuxunaffected: 6.12.113 through 6.12.*CVE List
  • Linuxunaffected: 6.18.57 through 6.18.*CVE List
  • Linuxunaffected: 7.2.11 through 7.2.*CVE List
  • Linuxunaffected: 7.3CVE List

References 5