CVE-2026-31609

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

CVE-2026-31609 is fixed in 19 products on 1 platform, first by DEBIAN-CVE-2026-31609, released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

9.8

Important

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0046

39th percentile

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.

Where it's fixed

Product	Fixed in	Fix	Released
Linux
bpftool6.18 · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
bpftool6.18-debuginfo · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel-livepatch-6.18.25-52.107 · amzn 2023	1:1.0-0.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18 · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-debuginfo · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-debuginfo-common-aarch64 · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-debuginfo-common-x86_64 · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-devel · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-headers · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-modules-extra · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-modules-extra-common · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-tools · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-tools-debuginfo · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
kernel6.18-tools-devel · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
linux · Debian 14	6.19.14-1	DEBIAN-CVE-2026-31609	May 15, 2026
perf6.18 · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
perf6.18-debuginfo · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
python3-perf6.18 · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026
python3-perf6.18-debuginfo · amzn 2023	1:6.18.25-52.107.amzn2023	ALAS2023-2026-1746	May 25, 2026

Details

Published
April 24, 2026
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31609

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