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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72124
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:21:29 UTC
Updated2026-08-19 17:20:59 UTC
DescriptionIn 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is still the one currently active, so they don't report an error against a transfer that has since completed or been superseded.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.003330000 probability, percentile 0.263530000 (date 2026-08-19)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary8.8HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.8HIGHCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 bbedeb67a9a684f2fb78c55bd3662c400526715e git Not specified
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 377a8f500704da42ed86a4541ed930e9dcfdb2ea git Not specified
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 6da8119e8dd542194103139812d1a4b7dcd1aedd git Not specified
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 0b05eca9589f609e2491b528dccf683168a4cda8 git Not specified
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 a7d90e7b5e75d7406c889fe36e9a61ee364a00cb git Not specified
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 37beb16e08cae94cc05840c7274225e3b0b38ae7 git Not specified
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 4f1fdf1a1c317bcac0c6b6c8e12642c9983de1ca git Not specified
CNA Linux Linux affected e057dd3fc20ffb3d7f150af46542a51b59b90127 cf070fe33bfbd1a4c21236078fadb35dd223a157 git Not specified
CNA Linux Linux affected 5.10 Not specified
CNA Linux Linux unaffected 5.10 semver Not specified
CNA Linux Linux unaffected 5.10.265 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.148 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.101 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/0b05eca9589f609e2491b528dccf683168a4cda8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6da8119e8dd542194103139812d1a4b7dcd1aedd 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bbedeb67a9a684f2fb78c55bd3662c400526715e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/cf070fe33bfbd1a4c21236078fadb35dd223a157 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/37beb16e08cae94cc05840c7274225e3b0b38ae7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/377a8f500704da42ed86a4541ed930e9dcfdb2ea 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4f1fdf1a1c317bcac0c6b6c8e12642c9983de1ca 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a7d90e7b5e75d7406c889fe36e9a61ee364a00cb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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