CVE-2026-31474
In the Linux kernel, the following vulnerability has been resolved: can: isotp: fix tx.buf use-after-free in isotp_sendmsg() isotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access to so->tx.buf. isotp_release() waits for ISOTP_IDLE via…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.10%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: can: isotp: fix tx.buf use-after-free in isotp_sendmsg() isotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access to so->tx.buf. isotp_release() waits for ISOTP_IDLE via wait_event_interruptible() and then calls kfree(so->tx.buf). If a signal interrupts the wait_event_interruptible() inside close() while tx.state is ISOTP_SENDING, the loop exits early and release proceeds to force ISOTP_SHUTDOWN and continues to kfree(so->tx.buf) while sendmsg may still be reading so->tx.buf for the final CAN frame in isotp_fill_dataframe(). The so->tx.buf can be allocated once when the standard tx.buf length needs to be extended. Move the kfree() of this potentially extended tx.buf to sk_destruct time when either isotp_sendmsg() and isotp_release() are done.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.10% probability · 1th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416, CWE-364
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/2e62e7051eca75a7f2e3d52d62ec10d7d7aa358cPatch
- https://git.kernel.org/stable/c/424e95d62110cdbc8fd12b40918f37e408e35a92Patch
- https://git.kernel.org/stable/c/9649d051e54413049c009638ec1dc23962c884a4Patch
- https://git.kernel.org/stable/c/cb3d6efa78460e6d50bf68806d0db66265709f64Patch
- https://git.kernel.org/stable/c/eec8a1b18a79600bd4419079dc0026c1db72a830Patch
- https://access.redhat.com/errata/RHSA-2026:27288
- https://access.redhat.com/errata/RHSA-2026:27731
- https://access.redhat.com/errata/RHSA-2026:27789
- https://access.redhat.com/security/cve/CVE-2026-31474
- https://bugzilla.redhat.com/show_bug.cgi?id=2460646
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31474.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.