can: isotp: serialize TX state transitions under so->rx_lock

Description

In the Linux kernel, the following vulnerability has been resolved: can: isotp: serialize TX state transitions under so->rx_lock The TX state machine (so->tx.state) is driven from three contexts: sendmsg() claiming and progressing a transfer, the RX path consuming Flow Control/echo frames, and two hrtimers timing out a stalled transfer. Mixing a lock-free cmpxchg() claim in sendmsg() with hrtimer_cancel() calls made under so->rx_lock elsewhere left windows where a frame or timer callback could act on a state that had already moved on, corrupting an unrelated transfer. so->rx_lock now covers the full lifecycle of a TX claim: sendmsg() takes it to check so->tx.state is ISOTP_IDLE, switch it to ISOTP_SENDING, bump so->tx_gen and drain the previous transfer's timers - all as one critical section. isotp_rcv_fc()/isotp_rcv_cf() already run under this lock via isotp_rcv(), and isotp_rcv_echo() now takes it itself, so none of them can ever observe a transfer mid-claim. This also means a transfer can no longer be handed to sendmsg()'s cleanup paths (signal or send error) while another thread is concurrently claiming or finishing it, so those paths can cancel timers and reset the state unconditionally. isotp_release() claims the socket the same way, so a racing sendmsg() sees a consistent ISOTP_SHUTDOWN and skips arming its timer or sending. Only the hrtimer callbacks stay outside so->rx_lock, since they run under so->rx_lock's cancellation elsewhere and taking it themselves would deadlock. so->tx_gen lets them recognize whether the transfer they timed out is still the one currently active, so they don't report an error against a transfer that has since completed or been superseded.

Timeline

Scores

EPSS (exploitation in 30 days)

0.35% · top 70% of all CVEs (12 Nov 2026)

CISA SSVC

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

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.

Affected products

• Linux · Linux

  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < bbedeb67a9a684f2fb78c55bd3662c400526715e
  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < 377a8f500704da42ed86a4541ed930e9dcfdb2ea
  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < 6da8119e8dd542194103139812d1a4b7dcd1aedd
  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < 0b05eca9589f609e2491b528dccf683168a4cda8
  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < a7d90e7b5e75d7406c889fe36e9a61ee364a00cb
  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < 37beb16e08cae94cc05840c7274225e3b0b38ae7
  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < 4f1fdf1a1c317bcac0c6b6c8e12642c9983de1ca
  • affected e057dd3fc20ffb3d7f150af46542a51b59b90127 – < cf070fe33bfbd1a4c21236078fadb35dd223a157

• Linux · Linux

  • affected 5.10
  • unaffected < 5.10
  • unaffected 5.10.265 – ≤ 5.10.*
  • unaffected 5.15.216 – ≤ 5.15.*
  • unaffected 6.1.183 – ≤ 6.1.*
  • unaffected 6.6.148 – ≤ 6.6.*
  • unaffected 6.12.101 – ≤ 6.12.*
  • unaffected 6.18.40 – ≤ 6.18.*
  • unaffected 7.1.5 – ≤ 7.1.*
  • unaffected 7.2 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-58882 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-72124](https://cveledger.app/badge/CVE-2026-72124.svg)](https://cveledger.app/cve/CVE-2026-72124)

Record last updated 16 Oct 2026, 18:44 UTC.