---
cve: "CVE-2026-31474"
severity: "HIGH"
cvss: 7.8
epss: "10%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-04-22 14:16:44"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T00:31:39+02:00"
---

# CVE-2026-31474

> 7.8 HIGH

## Beschreibung

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-Vektor

```
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Lokal | good |
| AC Komplexität | Gering | bad |
| PR Privilegien | Gering | warn |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 6.6.131
- Kernel ≥ 6.12.80
- Kernel ≥ 6.18.21
- Kernel ≥ 6.19.11

## Referenzen

- <https://git.kernel.org/stable/c/cb3d6efa78460e6d50bf68806d0db66265709f64>
- <https://git.kernel.org/stable/c/9649d051e54413049c009638ec1dc23962c884a4>
- <https://git.kernel.org/stable/c/eec8a1b18a79600bd4419079dc0026c1db72a830>
- <https://git.kernel.org/stable/c/2e62e7051eca75a7f2e3d52d62ec10d7d7aa358c>
- <https://git.kernel.org/stable/c/424e95d62110cdbc8fd12b40918f37e408e35a92>
- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-31474) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_