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Fencer Vulns
low 3.1

CVE-2026-35387 json

OpenSSH before 10.3 can use unintended ECDSA algorithms.

published 2026-04-02 7 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-18402 , JLSEC-2026-76

cvss
3.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 15%
public exploits
0
none known

Summary

OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.

Patch / fix

  • julia OpenSSH_jll 10.3.1+0
  • OpenBSD OpenSSH 10.3
  • openssh Debian 12 1:9.2p1-2+deb12u10
  • openssh Debian 13 1:10.0p1-7+deb13u3
  • openssh Debian 14 1:10.3p1-1

debian advisories DEBIAN-CVE-2026-35387

  • openssh Ubuntu 22.04 LTS 1:8.9p1-3ubuntu0.15
  • openssh Ubuntu 24.04 LTS 1:9.6p1-3ubuntu13.16
  • openssh Ubuntu 25.10 1:10.0p1-5ubuntu5.4
  • openssh Ubuntu 26.04 LTS 1:10.2p1-2ubuntu3.2
  • openssh Ubuntu Pro 14.04 LTS 1:6.6p1-2ubuntu2.13+esm4
  • openssh Ubuntu Pro 16.04 LTS 1:7.2p2-4ubuntu2.10+esm10
  • openssh Ubuntu Pro 18.04 LTS 1:7.6p1-4ubuntu0.7+esm6
  • openssh Ubuntu Pro 20.04 LTS 1:8.2p1-4ubuntu0.13+esm3

ubuntu advisories UBUNTU-CVE-2026-35387

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

  • openssh RHEL 9 9.9p1-7.el9_8
  • openssh-keycat RHEL 9 9.9p1-7.el9_8
  • openssh-server RHEL 9 9.9p1-7.el9_8
  • openssh-askpass RHEL 9 9.9p1-7.el9_8
  • openssh-clients RHEL 9 9.9p1-7.el9_8
  • pam_ssh_agent_auth RHEL 9 0.10.4-7.7.el9_8
  • openssh RHEL 10.2 9.9p1-23.el10_2
  • openssh-keycat RHEL 10.2 9.9p1-23.el10_2

red hat advisories RHSA-2026:22648RHSA-2026:22564RHSA-2026:22329RHSA-2026:21398RHSA-2026:21298RHSA-2026:19219

  • openssh AlmaLinux 10 9.9p1-23.el10_2.alma.1
  • openssh-keycat AlmaLinux 10 9.9p1-23.el10_2.alma.1
  • openssh-server AlmaLinux 10 9.9p1-23.el10_2.alma.1
  • openssh-askpass AlmaLinux 10 9.9p1-23.el10_2.alma.1
  • openssh-clients AlmaLinux 10 9.9p1-23.el10_2.alma.1
  • openssh-keysign AlmaLinux 10 9.9p1-23.el10_2.alma.1
  • openssh AlmaLinux 9 9.9p1-7.el9_8.alma.1
  • openssh-keycat AlmaLinux 9 9.9p1-7.el9_8.alma.1

almalinux advisories ALSA-2026:19069ALSA-2026:19219ALSA-2026:13380ALSA-2026:13381ALSA-2026:13383

  • openssh Rocky Linux 10 9.9p1-23.el10_2.rocky.0.1
  • openssh Rocky Linux 9 9.9p1-7.el9_8.rocky.0.1
  • openssh Rocky Linux 10 9.9p1-14.el10_1.rocky.0.1
  • openssh Rocky Linux 9 8.7p1-49.el9_7.rocky.0.1
  • openssh Rocky Linux 8 8.0p1-29.el8_10

rocky linux advisories RLSA-2026:19069RLSA-2026:19219RLSA-2026:13380RLSA-2026:13381RLSA-2026:13383

  • openssh Azure Linux 3.0 9.8p1-8

azure linux advisories AZL-81794

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-2026-35387 updated cvss 3.1

OpenSSH: OpenSSH: Information disclosure due to unintended cryptographic algorithm usage

  • Red Hat Enterprise Linux 6 openssh, openssh-ldap, openssh-server, openssh-askpass, openssh-clients, pam_ssh_agent_auth Red Hat Enterprise Linux 7 openssh, openssh-cavs, openssh-ldap, openssh-keycat, openssh-server, openssh-askpass, +3 more 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 AI Inference Server 3.2 rhaiis/model-opt-cuda-rhel9 1780681984
    fixed: vendor fix RHSA-2026:25096
  • Red Hat Discovery 2 discovery 1778101579
    fixed: vendor fix RHSA-2026:14937
  • Red Hat Enterprise Linux AppStream (v. 8) openssh-askpass 8.0p1-29.el8_10
    fixed: vendor fix RHSA-2026:13383
  • Red Hat Enterprise Linux AppStream (v. 9) openssh-askpass 9.9p1-7.el9_8, openssh-askpass 8.7p1-49.el9_7, pam_ssh_agent_auth 0.10.4-7.7.el9_8, pam_ssh_agent_auth 0.10.4-5.49.el9_7
    fixed: vendor fix RHSA-2026:13381
  • Red Hat Enterprise Linux AppStream (v. 10) openssh-askpass 9.9p1-14.el10_1, openssh-askpass 9.9p1-23.el10_2, openssh-keysign 9.9p1-14.el10_1, openssh-keysign 9.9p1-23.el10_2
    fixed: vendor fix RHSA-2026:13380
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) openssh-askpass 8.0p1-15.el8_6.5 Red Hat Enterprise Linux AppStream E4S (v.8.6) openssh-askpass 8.0p1-15.el8_6.5
    fixed: vendor fix RHSA-2026:21398
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) openssh-askpass 8.7p1-30.el9_2.11, pam_ssh_agent_auth 0.10.4-5.30.el9_2.11
    fixed: vendor fix RHSA-2026:22648
show 20 more
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) openssh-askpass 9.9p1-7.el10_0.3, openssh-keysign 9.9p1-7.el10_0.3
    fixed: vendor fix RHSA-2026:12389
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) openssh-askpass 8.7p1-38.el9_4.8, pam_ssh_agent_auth 0.10.4-5.38.el9_4.8
    fixed: vendor fix RHSA-2026:22564
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) openssh-askpass 8.7p1-45.el9_6.3, pam_ssh_agent_auth 0.10.4-5.45.el9_6.3
    fixed: vendor fix RHSA-2026:16059
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) openssh-askpass 8.0p1-15.el8_6.5
    fixed: vendor fix RHSA-2026:21398
  • Red Hat Enterprise Linux BaseOS (v. 8) openssh 8.0p1-29.el8_10, openssh-cavs 8.0p1-29.el8_10, openssh-ldap 8.0p1-29.el8_10, openssh-keycat 8.0p1-29.el8_10, openssh-server 8.0p1-29.el8_10, openssh-clients 8.0p1-29.el8_10, +1 more
    fixed: vendor fix RHSA-2026:13383
  • Red Hat Enterprise Linux BaseOS (v. 9) openssh 9.9p1-7.el9_8, openssh 8.7p1-49.el9_7, openssh-keycat 9.9p1-7.el9_8, openssh-server 9.9p1-7.el9_8, openssh-clients 9.9p1-7.el9_8, openssh-keycat 8.7p1-49.el9_7, +2 more
    fixed: vendor fix RHSA-2026:13381
  • Red Hat Enterprise Linux BaseOS (v. 10) openssh 9.9p1-14.el10_1, openssh 9.9p1-23.el10_2, openssh-keycat 9.9p1-14.el10_1, openssh-keycat 9.9p1-23.el10_2, openssh-server 9.9p1-14.el10_1, openssh-server 9.9p1-23.el10_2, +2 more
    fixed: vendor fix RHSA-2026:13380
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) openssh 8.0p1-7.el8_4.2, openssh-server 8.0p1-7.el8_4.2, openssh-clients 8.0p1-7.el8_4.2
    fixed: vendor fix RHSA-2026:22329
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) openssh 8.0p1-15.el8_6.5, openssh-cavs 8.0p1-15.el8_6.5, openssh-ldap 8.0p1-15.el8_6.5, openssh-keycat 8.0p1-15.el8_6.5, openssh-server 8.0p1-15.el8_6.5, openssh-clients 8.0p1-15.el8_6.5, +1 more Red Hat Enterprise Linux BaseOS E4S (v.8.6) openssh 8.0p1-15.el8_6.5, openssh-cavs 8.0p1-15.el8_6.5, openssh-ldap 8.0p1-15.el8_6.5, openssh-keycat 8.0p1-15.el8_6.5, openssh-server 8.0p1-15.el8_6.5, openssh-clients 8.0p1-15.el8_6.5, +1 more
    fixed: vendor fix RHSA-2026:21398
  • Red Hat Enterprise Linux BaseOS E4S (v.8.8) openssh 8.0p1-20.el8_8.4, openssh-server 8.0p1-20.el8_8.4, openssh-clients 8.0p1-20.el8_8.4
    fixed: vendor fix RHSA-2026:21298
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) openssh 8.7p1-30.el9_2.11, openssh-keycat 8.7p1-30.el9_2.11, openssh-server 8.7p1-30.el9_2.11, openssh-clients 8.7p1-30.el9_2.11
    fixed: vendor fix RHSA-2026:22648
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) openssh 9.9p1-7.el10_0.3, openssh-keycat 9.9p1-7.el10_0.3, openssh-server 9.9p1-7.el10_0.3, openssh-clients 9.9p1-7.el10_0.3
    fixed: vendor fix RHSA-2026:12389
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) openssh 8.7p1-38.el9_4.8, openssh-keycat 8.7p1-38.el9_4.8, openssh-server 8.7p1-38.el9_4.8, openssh-clients 8.7p1-38.el9_4.8
    fixed: vendor fix RHSA-2026:22564
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) openssh 8.7p1-45.el9_6.3, openssh-keycat 8.7p1-45.el9_6.3, openssh-server 8.7p1-45.el9_6.3, openssh-clients 8.7p1-45.el9_6.3
    fixed: vendor fix RHSA-2026:16059
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) openssh 8.0p1-7.el8_4.2, openssh-server 8.0p1-7.el8_4.2, openssh-clients 8.0p1-7.el8_4.2
    fixed: vendor fix RHSA-2026:22329
  • Red Hat Enterprise Linux BaseOS TUS (v.8.6) openssh 8.0p1-15.el8_6.5, openssh-cavs 8.0p1-15.el8_6.5, openssh-ldap 8.0p1-15.el8_6.5, openssh-keycat 8.0p1-15.el8_6.5, openssh-server 8.0p1-15.el8_6.5, openssh-clients 8.0p1-15.el8_6.5, +1 more
    fixed: vendor fix RHSA-2026:21398
  • Red Hat Enterprise Linux BaseOS TUS (v.8.8) openssh 8.0p1-20.el8_8.4, openssh-server 8.0p1-20.el8_8.4, openssh-clients 8.0p1-20.el8_8.4
    fixed: vendor fix RHSA-2026:21298
  • Red Hat OpenShift AI 3.4 rhai/base-image-neuron-rhel9 1790703542
    fixed: vendor fix RHSA-2026:74674
  • Red Hat Update Infrastructure 5 rhui5/rhua-rhel9 1779798222, rhui5/rhua-tp-rhel9 1787241260, rhui5/installer-rhel9 1779798165, rhui5/installer-tp-rhel9 1787135742
    fixed: vendor fix RHSA-2026:21275
  • Red Hat Discovery 2 discovery 1778156756 Red Hat Enterprise Linux AppStream AUS (v.8.4) openssh-askpass 8.0p1-7.el8_4.2 Red Hat Enterprise Linux AppStream AUS (v.8.6) openssh-askpass-debuginfo 8.0p1-15.el8_6.5 Red Hat Enterprise Linux AppStream E4S (v.8.6) openssh-askpass-debuginfo 8.0p1-15.el8_6.5 Red Hat Enterprise Linux AppStream E4S (v.8.8) openssh-askpass 8.0p1-20.el8_8.4 Red Hat Enterprise Linux AppStream EUS (v. 10.0) openssh-askpass-debuginfo 9.9p1-7.el10_0.3
    +3 more products
    Red Hat Enterprise Linux AppStream EUS (v.9.4) openssh-askpass-debuginfo 8.7p1-38.el9_4.8 Red Hat Enterprise Linux AppStream EUS (v.9.6) openssh-askpass-debuginfo 8.7p1-45.el9_6.3 Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) openssh-askpass 8.0p1-7.el8_4.2
    not affected: vulnerable code not present

13 more not affected in the full advisory

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
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 15% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

Affected packages

ecosystem package affected fixed in
julia OpenSSH_jll
<10.3.1+0
10.3.1+0

Affected products

  • OpenBSD OpenSSH

Classification

Weakness
  • CWE-670 Always-Incorrect Control Flow Implementation

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.