CVE-2026-31638

Description

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.

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CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0007

Probability of exploitation

0.21%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.2.1 — 6.6.135
linux	linux_kernel	6.7 — 6.12.82
linux	linux_kernel	6.13 — 6.18.23
linux	linux_kernel	6.19 — 6.19.13
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All
linux	linux_kernel	All

References

Advisories & Patches

https://git.kernel.org/stable/c/0c156aff8a2d4fa0d61db7837641975cf0e5452d https://git.kernel.org/stable/c/6331f1b24a3e85465f6454e003a3e6c22005a5c5 https://git.kernel.org/stable/c/8299ca146489664e3c0c90a3b8900d8335b1ede4 https://git.kernel.org/stable/c/9fb09861e2b8d1abfe2efaf260c9f1d30080ea38 https://git.kernel.org/stable/c/b8f66447448d6c305a51413a67ec8ed26aa7d1dd

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-31638? +

CVE-2026-31638 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0007, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-31638? +

CVE-2026-31638 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-31638? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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