Cloudanix VulnDB

CVE-2026-80889

None

CVSS

—

EPSS

0.2%

Published

Sep 4, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in how the Linux kernel manages certain network timers and states could let programs interfere with each other and cause crashes or errors during communication over specific hardware buses.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
High
Impact
Other
Component
OS kernel
Class
Race Condition
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Race conditions in Linux kernel CAN ISOTP socket timer draining, wakeup signaling, tx_gen ordering, and state transitions under so->rx_lock allow stale callbacks to re-arm timers, strand sleeping processes, corrupt concurrent release paths, or pair stale generation counters with fresh state on weakly ordered CPUs.

Why it matters to the business

Systems using CAN bus communication may experience kernel instability, unexpected socket errors, or denial of service during high-load or concurrent transmit/release operations, increasing downtime risk for automotive, industrial, or embedded deployments.

How an attack unfolds

An attacker with local access or control over CAN traffic triggers concurrent isotp_sendmsg and isotp_release calls, exploiting ordering windows in timer drains and generation counters so that a timeout or error path operates on the wrong transfer state, leading to corrupted results or stuck sockets.

How to fix it

Update to a Linux kernel containing the referenced isotp timer drain, wakeup, and tx_gen ordering fixes; rebuild and deploy the patched kernel image for all affected CAN-enabled systems.

How to confirm the fix worked

Confirm kernel version includes the cf070fe33bfb follow-up commit, exercise isotp sockets under concurrent load while monitoring for timer-related warnings or state inconsistencies, and verify absence of sashiko-bot reported races via static analysis or fuzzing.

Typical attack path

  1. Obtain local execution or CAN interface access on target system
  2. Open multiple ISOTP sockets and issue concurrent sendmsg/release operations
  3. Force timing windows via load or specific message patterns to hit stale timer or generation paths
  4. Observe kernel oops, socket errors, or resource leaks confirming state corruption

How to detect it

Review kernel logs for isotp-related warnings, timer callbacks, or state transition errors around CAN socket usage; inspect crash dumps for evidence of concurrent sendmsg/release paths; correlate with process activity on CAN interfaces.

What your security team should do

  • Prioritize kernel upgrade on any system exposing CAN ISOTP sockets within the next maintenance window
  • Restrict unprivileged local access and CAN interface usage until patched
  • Add kernel CAN socket usage to monitoring baselines for anomaly detection

The record

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.

Affected packages

Ecosystem Package Introduced Fixed