Double Free in Linux

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.

Vulnerability class: Double Free

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (50.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.1% 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-2026-31609: held from 0.005 to 0.007.

EPSS over last 30 days · oldest: 0.005 · newest: 0.007 · change: +0.002

Affected products

  • Linux — versions 6.18.24, 21538121efe6c8c5b51c742fa02cbe820bc48714, 7.0
  • Linux Kernel

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-31609?
CVE-2026-31609 is a critical-severity vulnerability in Linux, classified under Double Free. CVSS score: 9.8/10. Published 2026-04-24.
How severe is CVE-2026-31609?
Critical severity. CVSS v3 base score is 9.8 out of 10.