CVE-2026-31609: linux kernel Double Free — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush() smbd_send_batch_flush() already calls smbd_free_send_io(), so we should not call it again after smbd_post_send() moved it to the batch list.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0006

Probability of exploitation

0.19%

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-415 CWE-415

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 6.18.24
linux	linux_kernel	6.19 — 6.19.14
linux	linux_kernel	7.0 — 7.0.1

References

Advisories & Patches

https://git.kernel.org/stable/c/22b7c1c619d808aec4cad3dc42103345e370d107 https://git.kernel.org/stable/c/27b7c3e916218b5eb2ee350211140e961bfc49be https://git.kernel.org/stable/c/a9940dcbe5cb92482c04efc7341039ddf7dbf607 https://git.kernel.org/stable/c/f9a162c2bbcd0ac85bd07c5b37cf20286048b65c

Frequently Asked Questions

What is CVE-2026-31609? +

In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush() smbd_send_batch_flush() already calls smbd_free_send_io(), so we should not call it again after smbd_post_send() moved it to the batch list. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-31609? +

CVE-2026-31609 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0006, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-31609? +

CVE-2026-31609 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-2026-31609? +

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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