CVE catalog

CVE-2026-59843

A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to

[CVE catalog]

Severity: Medium · CVSS 6.7CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H
Published: Jul 20, 2026, 10:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.73% · Oct 27, 2026

A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	libssh	sid	`0.12.2-1`	fixed
Debian	libssh	forky	`0.12.2-1`	fixed
Debian	libssh	trixie	`0.11.5-0+deb13u1`	fixed
Debian	libssh	trixie-security	`0.11.5-0+deb13u1`	fixed
Debian	libssh	bookworm	`0.10.6-0+deb12u2`	vulnerable
Debian	libssh	bookworm-security	`0.10.6-0+deb12u3`	fixed
Cpe	libssh	Not reported	Not reported	vulnerable
Cpe	libssh	Not reported	Not reported	unknown
Cpe	hardened_images	Not reported	Not reported	unknown
Cpe	enterprise_linux	Not reported	Not reported	unknown
Ubuntu	libssh	noble	`0.10.6-2ubuntu0.5`	fixed
Ubuntu	libssh-4	noble	`0.10.6-2ubuntu0.5`	fixed
Ubuntu	libssh-dev	noble	`0.10.6-2ubuntu0.5`	fixed
Ubuntu	libssh-doc	noble	`0.10.6-2ubuntu0.5`	fixed
Ubuntu	libssh-gcrypt-4	noble	`0.10.6-2ubuntu0.5`	fixed
Ubuntu	libssh-gcrypt-dev	noble	`0.10.6-2ubuntu0.5`	fixed
Ubuntu	libssh	pro	`0.9.0-1ubuntu1`	vulnerable
Ubuntu	libssh	pro	`0.9.0-1ubuntu4`	vulnerable
Ubuntu	libssh	pro	`0.9.0-1ubuntu5`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu1`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.1`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.2`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.3`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.4`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.5`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.5+esm1`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.5+esm2`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.5+esm3`	vulnerable
Ubuntu	libssh	pro	`0.9.3-2ubuntu2.5+esm4`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-1`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-1build1`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2build1`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.1`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.2`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.3`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.4`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.5`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.6`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.7`	vulnerable
Ubuntu	libssh	22.04	`0.9.6-2ubuntu0.22.04.8`	fixed
Ubuntu	libssh	24.04	`0.10.5-3ubuntu1`	vulnerable
Ubuntu	libssh	24.04	`0.10.5-3ubuntu2`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2build1`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2build2`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2ubuntu0.1`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2ubuntu0.2`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2ubuntu0.3`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2ubuntu0.4`	vulnerable
Ubuntu	libssh	24.04	`0.10.6-2ubuntu0.5`	fixed
Ubuntu	libssh	26.04	`0.11.2-1build1`	vulnerable
Ubuntu	libssh	26.04	`0.11.3-1`	vulnerable
Ubuntu	libssh	26.04	`0.11.3-1ubuntu1`	vulnerable
Ubuntu	libssh	26.04	`0.11.3-1ubuntu2`	vulnerable
Ubuntu	libssh	26.04	`0.11.3-1ubuntu2.1`	fixed
Suse	libssh	linux micro 6.1	`0.10.6-slfo.1.1_6.1`	fixed
Suse	libssh	linux enterprise micro 5.3	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise micro 5.4	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise micro 5.5	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise high performance computing 15 sp4-espos	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise high performance computing 15 sp4-ltss	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise high performance computing 15 sp5-espos	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise high performance computing 15 sp5-ltss	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise server 15 sp4-ltss	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise server 15 sp5-ltss	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise server for sap applications 15 sp4	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise server for sap applications 15 sp5	`0.9.8-150400.3.20.1`	fixed
Suse	libssh	linux enterprise module for basesystem 15 sp7	`0.9.8-150600.11.15.1`	fixed
Suse	libssh	linux enterprise server 15 sp6-ltss	`0.9.8-150600.11.15.1`	fixed
Suse	libssh	linux enterprise server for sap applications 15 sp6	`0.9.8-150600.11.15.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	libssh	source	sid	`0.12.2-1`	not yet assigned	Not reported	Not reported
Debian	libssh	source	forky	`0.12.2-1`	not yet assigned	Not reported	Not reported
Debian	libssh	source	trixie	`0.11.5-0+deb13u1`	not yet assigned	Not reported	Not reported
Debian	libssh	source	bookworm	`0.10.6-0+deb12u3`	not yet assigned	Not reported	Not reported
Ubuntu	libssh	deb	noble	`0.10.6-2ubuntu0.5`	Not reported	Not reported	Not reported
Ubuntu	libssh-4	deb	noble	`0.10.6-2ubuntu0.5`	Not reported	Not reported	Not reported
Ubuntu	libssh-dev	deb	noble	`0.10.6-2ubuntu0.5`	Not reported	Not reported	Not reported
Ubuntu	libssh-doc	deb	noble	`0.10.6-2ubuntu0.5`	Not reported	Not reported	Not reported
Ubuntu	libssh-gcrypt-4	deb	noble	`0.10.6-2ubuntu0.5`	Not reported	Not reported	Not reported
Ubuntu	libssh-gcrypt-dev	deb	noble	`0.10.6-2ubuntu0.5`	Not reported	Not reported	Not reported
Ubuntu	libssh	deb	22.04	`0.9.6-2ubuntu0.22.04.8`	Not reported	UBUNTU-CVE-2026-59843	Not reported
Ubuntu	libssh	deb	24.04	`0.10.6-2ubuntu0.5`	Not reported	UBUNTU-CVE-2026-59843	Not reported
Ubuntu	libssh	deb	26.04	`0.11.3-1ubuntu2.1`	Not reported	UBUNTU-CVE-2026-59843	Not reported
Suse	libssh	rpm	linux micro 6.1	`0.10.6-slfo.1.1_6.1`	Not reported	SUSE-SU-2026:23168-1	Not reported
Suse	libssh	rpm	linux enterprise micro 5.3	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise micro 5.4	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise micro 5.5	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise high performance computing 15 sp4-espos	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise high performance computing 15 sp4-ltss	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise high performance computing 15 sp5-espos	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise high performance computing 15 sp5-ltss	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise server 15 sp4-ltss	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise server 15 sp5-ltss	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise server for sap applications 15 sp4	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise server for sap applications 15 sp5	`0.9.8-150400.3.20.1`	Not reported	SUSE-SU-2026:3463-1	Not reported
Suse	libssh	rpm	linux enterprise module for basesystem 15 sp7	`0.9.8-150600.11.15.1`	Not reported	SUSE-SU-2026:3330-1	Not reported
Suse	libssh	rpm	linux enterprise server 15 sp6-ltss	`0.9.8-150600.11.15.1`	Not reported	SUSE-SU-2026:3330-1	Not reported
Suse	libssh	rpm	linux enterprise server for sap applications 15 sp6	`0.9.8-150600.11.15.1`	Not reported	SUSE-SU-2026:3330-1	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[libssh-4]Affected
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
[libssh-dev]Affected
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
[libssh-doc]Affected
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · all · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u2 · all · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · all · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · all · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
[libssh-gcrypt-4]Affected
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
[libssh-gcrypt-dev]Affected
Source package: [libssh]
Details (4)
- 0.10.6-0+deb12u2 · amd64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u2 · arm64 · bookworm
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · amd64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12
- 0.10.6-0+deb12u1 · arm64 · bookworm-security
  Affected · Fixed: 0.10.6-0+deb12u3
  nvd · libssh · debian · bookworm; nvd · libssh · debian · 12

[Debian 13 (Trixie)]

[libssh-4]Affected
Source package: [libssh]
Details (4)
- 0.11.2-1+deb13u1 · amd64 · trixie
  Affected · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.2-1+deb13u1 · arm64 · trixie
  Affected · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.5-0+deb13u1 · amd64 · trixie-security
  Fixed · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.5-0+deb13u1 · arm64 · trixie-security
  Fixed · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
[libssh-dev]Affected
Source package: [libssh]
Details (4)
- 0.11.2-1+deb13u1 · amd64 · trixie
  Affected · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.2-1+deb13u1 · arm64 · trixie
  Affected · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.5-0+deb13u1 · amd64 · trixie-security
  Fixed · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.5-0+deb13u1 · arm64 · trixie-security
  Fixed · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
[libssh-doc]Affected
Source package: [libssh]
Details (4)
- 0.11.2-1+deb13u1 · all · trixie
  Affected · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.2-1+deb13u1 · all · trixie
  Affected · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.5-0+deb13u1 · all · trixie-security
  Fixed · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13
- 0.11.5-0+deb13u1 · all · trixie-security
  Fixed · Fixed: 0.11.5-0+deb13u1
  nvd · libssh · debian · 13

Observed: Oct 27, 2026, 7:12:47 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]