{"id":"CVE-2026-31474","title":"can: isotp: fix tx.buf use-after-free in isotp_sendmsg()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: isotp: fix tx.buf use-after-free in isotp_sendmsg()\n\nisotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access\nto so->tx.buf. isotp_release() waits f…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < cb3d6efa78460e6d50bf68806d0db66265709f64","Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < 9649d051e54413049c009638ec1dc23962c884a4","Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < eec8a1b18a79600bd4419079dc0026c1db72a830","Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < 2e62e7051eca75a7f2e3d52d62ec10d7d7aa358c","Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < 424e95d62110cdbc8fd12b40918f37e408e35a92","Linux 6.4"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:09:55.947236Z"},"published":"2026-04-22","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:20:12.522Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-31474","references":[{"url":"https://git.kernel.org/stable/c/cb3d6efa78460e6d50bf68806d0db66265709f64"},{"url":"https://git.kernel.org/stable/c/9649d051e54413049c009638ec1dc23962c884a4"},{"url":"https://git.kernel.org/stable/c/eec8a1b18a79600bd4419079dc0026c1db72a830"},{"url":"https://git.kernel.org/stable/c/2e62e7051eca75a7f2e3d52d62ec10d7d7aa358c"},{"url":"https://git.kernel.org/stable/c/424e95d62110cdbc8fd12b40918f37e408e35a92"}],"tags":["cve.org"],"epss":0.00142,"epssPercentile":0.03102,"ingestedAt":"2026-10-16T17:24:46.655Z","slug":"CVE-2026-31474","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ncan: isotp: fix tx.buf use-after-free in isotp_sendmsg()\n\nisotp_sendmsg() uses only cmpxchg() on so->tx.state to serialize access\nto so->tx.buf. isotp_release() waits for ISOTP_IDLE via\nwait_event_interruptible() and then calls kfree(so->tx.buf).\n\nIf a signal interrupts the wait_event_interruptible() inside close()\nwhile tx.state is ISOTP_SENDING, the loop exits early and release\nproceeds to force ISOTP_SHUTDOWN and continues to kfree(so->tx.buf)\nwhile sendmsg may still be reading so->tx.buf for the final CAN frame\nin isotp_fill_dataframe().\n\nThe so->tx.buf can be allocated once when the standard tx.buf length needs\nto be extended. Move the kfree() of this potentially extended tx.buf to\nsk_destruct time when either isotp_sendmsg() and isotp_release() are done.\n\n## Affected\n\n- `Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < cb3d6efa78460e6d50bf68806d0db66265709f64`\n- `Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < 9649d051e54413049c009638ec1dc23962c884a4`\n- `Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < eec8a1b18a79600bd4419079dc0026c1db72a830`\n- `Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < 2e62e7051eca75a7f2e3d52d62ec10d7d7aa358c`\n- `Linux >= 96d1c81e6a0478535342dff6c730adb076cd84e8 < 424e95d62110cdbc8fd12b40918f37e408e35a92`\n- `Linux 6.4`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}