What’s Vulnerable › Vulnerabilities

CVE-2026-31609: smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-24 · updated 2026-10-19
• Weakness: CWE-415

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.

Affected products

• Linux kernel: before 6.18.24; from 6.19 before 6.19.14; from 7.0 before 7.0.1 — fixed in 6.18.24, 6.19.14, 7.0.1

How to fix

Upgrade to a fixed version: Linux kernel 6.18.24, 6.19.14, 7.0.1. Check the vendor advisory for mitigations.

References

• 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

Get alerted when CVE-2026-31609 or the next vulnerability affects your stack