CVE-2026-80889
Received
Received - Intake
Race Condition in Linux Kernel CAN ISOTP
Vulnerability report for CVE-2026-80889, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-04
Last updated on: 2026-09-04
Assigner: kernel.org
Description
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux_kernel | linux_kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
