NULL pointer dereference in Linux

CVE-2026-31638

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Only put the call ref if one was acquired rxrpc_input_packet_on_conn() can process a to-client packet after the current client call on the channel has already been torn down. In that case chan->call is NULL, rxrpc_try_get_call() returns NULL and there is no reference to drop. The client-side implicit-end error path does not account for that and unconditionally calls rxrpc_put_call(). This turns a protocol error path into a kernel crash instead of rejecting the packet. Only drop the call reference if one was actually acquired. Keep the existing protocol error handling unchanged.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.006 (48.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-31638: held from 0.004 to 0.006.

EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002

Affected products

  • Linux — versions 5e6ef4f1017c7f844e305283bbd8875af475e2fc, 6.2, 0
  • Linux Kernel — versions 6.2, 7.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-31638?
CVE-2026-31638 is a high-severity vulnerability in Linux, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2026-04-24.
How severe is CVE-2026-31638?
High severity. CVSS v3 base score is 7.5 out of 10.