CVE-2026-3591

A stack use-after-return flaw in SIG(0) handling code may enable ACL bypass

CVE-2026-3591 is fixed in 6 products on 1 platform, first by DEBIAN-CVE-2026-3591, released March 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.

Routine

CVSS

5.4

Moderate

Exploitation

None reported

No vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0038

31st percentile

stack use-after-return flaw in SIG(0) handling code allows for ACL bypass (bsc#1260569).

Where it's fixed

Product	Fixed in	Fix	Released
Linux
bind · opensuse-leap 16.0	9.20.21-160000.1.1	OPENSUSE-SU-2026:20550-1	Apr 16, 2026
bind · sles 15.7	9.20.21-150700.3.18.1	SUSE-SU-2026:1351-1	Apr 15, 2026
bind · sles 16.0	9.20.21-160000.1.1	SUSE-SU-2026:21204-1	Apr 16, 2026
bind9 · Debian 13.5 (trixie)	1:9.20.21-1~deb13u1	DEBIAN-CVE-2026-3591	Mar 25, 2026
bind9 · Debian 14	1:9.20.21-1	DEBIAN-CVE-2026-3591	Mar 25, 2026
bind9 · Ubuntu 25.10 (questing)	1:9.20.11-1ubuntu2.2	bind9 1:9.20.11-1ubuntu2.2	Apr 15, 2026
bind9-dnsutils · Ubuntu 25.10 (questing)	1:9.20.11-1ubuntu2.2	bind9-dnsutils 1:9.20.11-1ubuntu2.2	Apr 15, 2026
bind9-host · Ubuntu 25.10 (questing)	1:9.20.11-1ubuntu2.2	bind9-host 1:9.20.11-1ubuntu2.2	Apr 15, 2026
bind9-libs · Ubuntu 25.10 (questing)	1:9.20.11-1ubuntu2.2	bind9-libs 1:9.20.11-1ubuntu2.2	Apr 15, 2026
bind9-utils · Ubuntu 25.10 (questing)	1:9.20.11-1ubuntu2.2	bind9-utils 1:9.20.11-1ubuntu2.2	Apr 15, 2026

Details

Published
March 24, 2026
Weakness
Return of Stack Variable Address
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-3591

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