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Fencer Vulns
medium 5.3

CVE-2026-3731 json

libssh SFTP Extension Name sftp.c sftp_extensions_get_data out-of-bounds

published 2026-03-08 8 mo ago modified 2026-07-25 3 mo ago also EUVD-2026-10234 , JLSEC-2026-784

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 54%
public exploits
0
none known

Summary

A weakness has been identified in libssh up to 0.11.3. The impacted element is the function sftp_extensions_get_name/sftp_extensions_get_data of the file src/sftp.c of the component SFTP Extension Name Handler. Executing a manipulation of the argument idx can lead to out-of-bounds read. The attack may be performed from remote. Upgrading to version 0.11.4 and 0.12.0 is sufficient to resolve this issue. This patch is called 855a0853ad3abd4a6cd85ce06fce6d8d4c7a0b60. You should upgrade the affected component.

Patch / fix

  • julia libssh_jll 0.11.4+0
  • n/a libssh 0.11.4, 0.12.0
  • libssh Debian 12 0.10.6-0+deb12u3
  • libssh Debian 13 0.11.5-0+deb13u1
  • libssh Debian 14 0.12.0-1

debian advisories DEBIAN-CVE-2026-3731

  • libssh Ubuntu 22.04 LTS 0.9.6-2ubuntu0.22.04.7
  • libssh Ubuntu 24.04 LTS 0.10.6-2ubuntu0.4
  • libssh Ubuntu 25.10 0.11.2-1ubuntu0.3
  • libssh Ubuntu 26.04 LTS 0.11.3-1ubuntu2
  • libssh Ubuntu Pro 16.04 LTS 0.6.3-4.3ubuntu0.6+esm5
  • libssh Ubuntu Pro 18.04 LTS 0.8.0~20170825.94fa1e38-1ubuntu0.7+esm7
  • libssh Ubuntu Pro 20.04 LTS 0.9.3-2ubuntu2.5+esm4

ubuntu advisories UBUNTU-CVE-2026-3731

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libssh hummingbird 1 0.12.0-1.1.hum1
  • libssh-config hummingbird 1 0.12.0-1.1.hum1

red hat advisories RHSA-2026:7067

  • libssh Linux Micro 6.0 0.10.6-5.1
  • libssh SLE Micro 5.5, SLE Micro 5.4, SLE Micro 5.3 0.9.8-150400.3.17.1
  • libssh SLE Module for Basesystem 15 SP7, openSUSE Leap 15.6 0.9.8-150600.11.12.1
  • libssh SLE Micro 5.2 0.9.8-150200.13.18.1
  • libssh Linux Micro 6.1 0.10.6-slfo.1.1_5.1
  • libssh SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 0.9.8-3.24.1
  • libssh SLES LTSS Extended Security 12 SP5 0.6.3-12.28.1

suse advisories SUSE-SU-2026:23056-1SUSE-SU-2026:3302-1SUSE-SU-2026:1565-1SUSE-SU-2026:1344-1SUSE-SU-2026:1310-1SUSE-SU-2026:0936-1

  • libssh Azure Linux 3.0 0.10.6-6

azure linux advisories AZL-79547

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-3731 updated cvss 5.3

libssh: libssh: Denial of Service via out-of-bounds read in SFTP extension name handler

  • Red Hat Enterprise Linux 6 libssh2 Red Hat Enterprise Linux 7 libssh2 Red Hat Enterprise Linux 8 libssh, libssh-config Red Hat Enterprise Linux 9 libssh, libssh-config Red Hat Enterprise Linux 10 libssh Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Hardened Images libssh 0.12.0-1.1.hum1, libssh-config 0.12.0-1.1.hum1
    fixed: vendor fix RHSA-2026:7067

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.72% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:X/RL:O/RC:C
CNA 3.0 5.3 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:X/RL:O/RC:C
CNA 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P/E:ND/RL:OF/RC:C
CNA 4.0 6.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
julia libssh_jll
<0.11.4+0
0.11.4+0

Affected products

  • n/a libssh

Classification

Weakness
  • CWE-125 Out-of-bounds Read
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.