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CVE-2026-72125

can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: can: isotp: fix use-after-free race with concurrent NETDEV_UNREGISTER isotp_release() looked up the bound network device via dev_get_by_index() using the stored ifindex. During device unregistration the device is unlisted from the ifindex hash before the NETDEV_UNREGISTER notifier chain runs, so a concurrent isotp_release() could find no device, skip can_rx_unregister() entirely, and still proceed to free the socket. Since isotp_release() had already removed itself from the isotp notifier list at that point, isotp_notify() would never get a chance to clean up either, leaving a stale CAN filter that keeps pointing at the freed socket. Fix this the same way raw.c already does: hold a tracked reference to the bound net_device in the socket (so->dev/so->dev_tracker) from bind() onward instead of re-resolving it from the ifindex, and serialize bind()/release() with rtnl_lock() so that so->dev is always consistent with what the NETDEV_UNREGISTER notifier sees. so->dev stays valid regardless of ifindex-hash unlisting, and is only ever cleared by whichever of isotp_release()/isotp_notify() gets there first, so the filter is always removed exactly once. isotp_bind() now rejects a (re)bind with -EAGAIN while so->[tx|rx].state isn't ISOTP_IDLE yet, so a timer left running by a prior NETDEV_UNREGISTER can't act on a newly bound so->ifindex. Both checks share the same lock_sock() section, so there is no window in which a concurrent isotp_notify() clearing so->bound could be missed.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected e057dd3fc20ffb3d7f150af46542a51b59b90127 before f311bbb29bb06aaab69ba45a6e4b11323d20b8f9; affected e057dd3fc20ffb3d7f150af46542a51b59b90127 before 8e018f4335590460ebcf0c2b493ed38ba1a35204; affected e057dd3fc20ffb3d7f150af46542a51b59b90127 before 33b9cd9245e2a4b800f99ed1cc53d64960614152; affected e057dd3fc20ffb3d7f150af46542a51b59b90127 before 0b811c4bbe3ec9ad611e90a540fe8b51b3bb8a96; affected e057dd3fc20ffb3d7f150af46542a51b59b90127 before 43884dc7963beef2328f507f4fe680bdc173eb80; affected e057dd3fc20ffb3d7f150af46542a51b59b90127 before 7bef39ba76eb7307ed22a50329e0f5776dbeda58; affected e057dd3fc20ffb3d7f150af46542a51b59b90127 before e442b62ba5a7756c17e05a77b32cdd085a2b6138; affected e057dd3fc20ffb3d7f150af46542a51b59b90127 before 20bab8b88baac140ca3701116e1d486c7f51e311
Linux / Linuxaffected 5.10; unaffected 0 before 5.10; unaffected 5.10.265 through 5.10.*; unaffected 5.15.216 through 5.15.*; unaffected 6.1.183 through 6.1.*; unaffected 6.6.148 through 6.6.*; unaffected 6.12.101 through 6.12.*; unaffected 6.18.40 through 6.18.*; unaffected 7.1.5 through 7.1.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.