CVE-2026-80889 is a vulnerability in Linux Kernel
Published on September 4, 2026
can: isotp: fix timer drain order, wakeup handling and tx_gen ordering
In the Linux kernel, the following vulnerability has been resolved:
can: isotp: fix timer drain order, wakeup handling and tx_gen ordering
This patch is a follow-up to commit cf070fe33bfb ("can: isotp: serialize
TX state transitions under so->rx_lock") which addresses following
sashiko-bot findings:
- isotp_sendmsg(): drain so->txfrtimer first so a stale callback can't
re-arm echotimer after the claim
- isotp_release(): wake so->wait after forcing ISOTP_SHUTDOWN so a
sleeping sendmsg() claim isn't stranded
- isotp_sendmsg(): have both wait_event_interruptible() calls in
isotp_sendmsg() also wake on ISOTP_SHUTDOWN and do not return claim to
IDLE to avoid corrupting a concurrent isotp_release() process.
- isotp_sendmsg(): handle potential claim of a new transfer when
the wait_event_interruptible() call returns in CAN_ISOTP_WAIT_TX_DONE
mode. Don't touch timers and states of the new transfer if a new thread
incremented so->tx_gen before getting the lock at err_event_drop.
- isotp_sendmsg(): handle a stuck can_send() and omit timer and state
changes if a new transfer was claimed. wait_tx_done() returns the error
recorded in so->tx_result[], tagged with the caller's own generation.
- isotp_tx_timeout(): on a claimed timeout, record the ECOMM error for
the timed-out transfer's own generation in so->tx_result[]; sk->sk_err
is raised unconditionally, same as every other error path here.
- isotp_tx_gen_done()/isotp_tx_timeout(): always read tx.state (acquire)
before tx_gen - the reverse order let a weakly ordered CPU pair a fresh
tx.state with a stale tx_gen/tx_result slot.
- isotp_sendmsg(): wait_tx_done: drain sk_err via sock_error() once we
have read the result from so->tx_result[], so an already-reported error
doesn't stay latched for a later poll()/SO_ERROR.
Also align the remaining lock-free so->tx.state/rx.state/cfecho accesses
and use skb->hash as unique loopback echo frame indicator.
Products Associated with CVE-2026-80889
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Affected Versions
Linux:- Version bbedeb67a9a684f2fb78c55bd3662c400526715e and below 8acab9fc66d6f426c36968c91a979f70784945a7 is affected.
- Version 377a8f500704da42ed86a4541ed930e9dcfdb2ea and below af7e25c649ed68cbad07f8185af0f31b892cbf29 is affected.
- Version 6da8119e8dd542194103139812d1a4b7dcd1aedd and below 2753722612d8824d3910096f93059f669009b0f0 is affected.
- Version 0b05eca9589f609e2491b528dccf683168a4cda8 and below bf5c4a8b24acb12739ebb9aea5510b007e4f5239 is affected.
- Version a7d90e7b5e75d7406c889fe36e9a61ee364a00cb and below deca7746b57d982cd4f0301f4443f56780c4a048 is affected.
- Version 37beb16e08cae94cc05840c7274225e3b0b38ae7 and below 10be509fa8fd95d1e47d40d1f68b0b26dfe9d572 is affected.
- Version 4f1fdf1a1c317bcac0c6b6c8e12642c9983de1ca and below 35c62ac98d06669aa3f0f38b7829eaca929a611e is affected.
- Version cf070fe33bfbd1a4c21236078fadb35dd223a157 and below 050f010f920da17c1044a4f174766ad553e770b6 is affected.
- Version 5.10.265 and below 5.10.267 is affected.
- Version 5.15.216 and below 5.15.218 is affected.
- Version 6.1.183 and below 6.1.185 is affected.
- Version 6.6.148 and below 6.6.151 is affected.
- Version 6.12.101 and below 6.12.103 is affected.
- Version 6.18.40 and below 6.18.44 is affected.
- Version 7.1.5 and below 7.1.8 is affected.