CVE-2026-59844 — Libssh: libssh: denial of service via oversized sftp read length

Description

A flaw was found in libssh. A remote authenticated client can issue SSH_FXP_READ requests with an arbitrarily large length, causing a libssh SFTP server to allocate excessive memory and potentially exhaust it through repeated requests.

Affected products

Vendor	Product	Affected	Fixed
Red Hat	Red Hat Enterprise Linux 10	—	—
Red Hat	Red Hat Enterprise Linux 8	—	—
Red Hat	Red Hat Enterprise Linux 9	—	—
Red Hat	Red Hat Hardened Images	—	—

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

Debian

Security tracker ↗

Release	Package	Fixed in	Advisory
Debian 14	libssh	0.12.1-1	—
Debian 13	libssh	0.11.5-0+deb13u1	—
Debian 12	libssh	0.10.6-0+deb12u3	—

Ubuntu

Security tracker ↗

Release	Package	Fixed in	Advisory
Ubuntu 26.04 LTS	libssh	0.11.3-1ubuntu2.1	USN-8699-1
Ubuntu 24.04 LTS	libssh	0.10.6-2ubuntu0.5	USN-8699-1
Ubuntu 22.04 LTS	libssh	0.9.6-2ubuntu0.22.04.8	USN-8699-1

Red Hat

Security tracker ↗

Release	Package	Fixed in	Advisory
RHEL 10	libssh +2	0.12.0-3.el10_2	RHSA-2026:55855
RHEL 9	libssh +2	0.10.4-19.el9_8	RHSA-2026:62217
RHEL 8	libssh +2	0.9.6-17.el8_10	RHSA-2026:62218

Show 1 more (older releases, extended support, other products)

Release	Package	Fixed in	Advisory
Red Hat Hardened Images 1	libssh +2	0.12.1-4.hum1	RHSA-2026:42922

AlmaLinux

Errata ↗

Release	Package	Fixed in	Advisory
AlmaLinux 10	libssh +2	0.12.0-3.el10_2	ALSA-2026:55855
AlmaLinux 9	libssh +2	0.10.4-19.el9_8	ALSA-2026:62217
AlmaLinux 8	libssh +2	0.9.6-17.el8_10	ALSA-2026:62218

Rocky Linux

Errata ↗

Release	Package	Fixed in	Advisory
Rocky Linux 10	libssh	0.12.0-3.el10_2	RLSA-2026:55855
Rocky Linux 9	libssh	0.10.4-19.el9_8	RLSA-2026:62217
Rocky Linux 8	libssh	0.9.6-17.el8_10	RLSA-2026:62218

SUSE

Security tracker ↗

Release	Package	Fixed in	Advisory
SLES 15 SP7	libssh	0.9.8-150600.11.15.1	SUSE-SU-2026:3330-1
SLES 15 SP6	libssh	0.9.8-150600.11.15.1	SUSE-SU-2026:3330-1
SLES 15 SP5	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLES 15 SP4	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLES 12 SP5	libssh	0.9.8-3.24.1	SUSE-SU-2026:3302-1

Show 13 more (older releases, extended support, other products)

Release	Package	Fixed in	Advisory
SLES for SAP 16.0	libssh	0.11.5-160000.1.1	SUSE-SU-2026:22956-1, SUSE-SU-2026:22948-1
SLES for SAP 15 SP6	libssh	0.9.8-150600.11.15.1	SUSE-SU-2026:3330-1
SLES for SAP 15 SP5	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLES for SAP 15 SP4	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLES 16.0	libssh	0.11.5-160000.1.1	SUSE-SU-2026:22956-1, SUSE-SU-2026:22948-1
SLE Micro 6.2	libssh	0.11.5-160000.1.1	SUSE-SU-2026:22940-1
SLE Micro 6.1	libssh	0.10.6-slfo.1.1_6.1	SUSE-SU-2026:23168-1
SLE Micro 6.0	libssh	0.10.6-5.1	SUSE-SU-2026:23056-1
SLE Micro 5.5	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLE Micro 5.4	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLE Micro 5.3	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLE HPC 15 SP5	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1
SLE HPC 15 SP4	libssh	0.9.8-150400.3.20.1	SUSE-SU-2026:3463-1

openSUSE

Security tracker ↗

Release	Package	Fixed in	Advisory
openSUSE Tumbleweed	libssh	0.11.5-1.2	openSUSE-SU-2026:11377-1
openSUSE Leap 16.0	libssh	0.11.5-160000.1.1	openSUSE-SU-2026:21444-1

Alpine

Security tracker ↗

Release	Package	Fixed in	Advisory
Alpine v3.24	libssh	0.12.1-r0	—

Amazon Linux

Release	Package	Fixed in	Advisory
Amazon Linux 2023	libssh +2	0.10.6-1.amzn2023.0.9	ALAS2023-2026-3096

Azure Linux

Release	Package	Fixed in	Advisory
Azure Linux 3	libssh	0.10.6-9	—

Oracle Linux

Release	Package	Fixed in	Advisory
Oracle Linux 10	libssh +2	0.12.0-3.el10_2	ELSA-2026-55855

Wolfi

Release	Package	Fixed in	Advisory
Wolfi rolling	libssh +1	0.12.1-r0	—

Advisories 25

WID-SEC-2026-3595 IBM QRadar SIEM: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
ALSA-2026:62217 Moderate: libssh security update AlmaLinux Security Advisories · Oct 29, 2026
ALSA-2026:55855 Important: libssh security update AlmaLinux Security Advisories · Oct 29, 2026
ALSA-2026:62218 Moderate: libssh security update AlmaLinux Security Advisories · Oct 29, 2026
WID-SEC-2026-2428 libssh: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 22, 2026
RHSA-2026:42922 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 6, 2026
ALAS2023-2026-3096 Moderate: libssh security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 28, 2026
RHSA-2026:62217 Red Hat Security Advisory: libssh security update Red Hat Security Advisories (RHSA) · Sep 2, 2026
RHSA-2026:62218 Red Hat Security Advisory: libssh security update Red Hat Security Advisories (RHSA) · Sep 2, 2026
RHSA-2026:55855 Red Hat Security Advisory: libssh security update Red Hat Security Advisories (RHSA) · Sep 2, 2026
RLSA-2026:62217 Moderate: libssh security update Rocky Linux Security Advisories · Sep 2, 2026
RLSA-2026:62218 Moderate: libssh security update Rocky Linux Security Advisories · Sep 2, 2026
USN-8699-1 libssh vulnerabilities Ubuntu Security Notices (USN) · Aug 31, 2026
SUSE-SU-2026:23168-1 Security update for libssh SUSE / openSUSE Security Updates · Aug 22, 2026
RLSA-2026:55855 Important: libssh security update Rocky Linux Security Advisories · Aug 18, 2026
ELSA-2026-55855 Important: libssh security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Aug 17, 2026
SUSE-SU-2026:23056-1 Security update for libssh SUSE / openSUSE Security Updates · Aug 12, 2026
SUSE-SU-2026:3463-1 Security update for libssh SUSE / openSUSE Security Updates · Aug 4, 2026
SUSE-SU-2026:3330-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 29, 2026
SUSE-SU-2026:22948-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 29, 2026
SUSE-SU-2026:22956-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 29, 2026
SUSE-SU-2026:22940-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 29, 2026
SUSE-SU-2026:3302-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 28, 2026
openSUSE-SU-2026:11377-1 libssh-config-0.11.5-1.1 on GA media SUSE / openSUSE Security Updates · Jul 27, 2026
openSUSE-SU-2026:21444-1 Security update for libssh SUSE / openSUSE Security Updates · Jul 26, 2026

References

RHSA-2026:42922 vendor-advisory
RHSA-2026:55855 vendor-advisory
RHSA-2026:62217 vendor-advisory
RHSA-2026:62218 vendor-advisory
https://access.redhat.com/security/cve/CVE-2026-59844 vdb-entry
RHBZ#2498177 issue-tracking

CNA	v3.1	6.5
EUVD	v3.1	6.5