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Fencer Vulns
high 7.5

CVE-2024-39894 json

OpenSSH 9.5 through 9.7 before 9.8 sometimes allows timing attacks against echo-off password entry (e.g., for su and Sudo) because of an Ob…

published 2024-07-02 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-38350

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

OpenSSH 9.5 through 9.7 before 9.8 sometimes allows timing attacks against echo-off password entry (e.g., for su and Sudo) because of an ObscureKeystrokeTiming logic error. Similarly, other timing attacks against keystroke entry could occur.

Patch / fix

  • openbsd openssh 9.8
  • openssh Debian 14, Debian 13 1:9.8p1-1

debian advisories DEBIAN-CVE-2024-39894

  • openssh Ubuntu 24.04 LTS 1:9.6p1-3ubuntu13.4

ubuntu advisories UBUNTU-CVE-2024-39894

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 Linux Micro 6.0 9.6p1-2.1
  • openssh SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 9.6p1-150600.6.6.1
  • openssh-askpass-gnome SLE Module for Desktop Applications 15 SP6, openSUSE Leap 15.6 9.6p1-150600.6.6.1

suse advisories SUSE-SU-2025:20009-1SUSE-SU-2024:2393-1

  • openssh openSUSE Tumbleweed 9.6p1-11.1

opensuse advisories openSUSE-SU-2024:14113-1

  • openssh Azure Linux 3.0 9.8p1-1

azure linux advisories AZL-43140

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-2024-39894 updated cvss 3.1

openssh: Logic error in ObscureKeystrokeTiming

  • 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 Enterprise Linux 8 openssh, openssh-cavs, openssh-ldap, openssh-keycat, openssh-server, openssh-askpass, +2 more Red Hat Enterprise Linux 9 openssh, openssh-keycat, openssh-server, openssh-askpass, openssh-clients, pam_ssh_agent_auth Red Hat Enterprise Linux 10 openssh Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    not affected: vulnerable code not present

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
total
Assessed
2 y ago

Exploit prediction

1.63% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • openbsd openssh

Classification

Weakness
  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.