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01 Record

CVE-2021-3634

A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other

UnratedPUBLISHEDCNA: redhat
CNA base scoreUnratedNo CNA CVSS vector
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02 Description

A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
4.68% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 91.4% of scored records. A rank, not a probability.
NVD base score
6.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Low. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2021-08-31 00:00Z5 YR AGO
Last updated
2024-08-03 17:01Z2 YR AGO
Reserved
2021-07-02
Assigning CNA
redhat
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
Data version
5.1
Document digest
f0efa60794df6652fb9be48f98e35ac58bd03d8213d35a69bbf170a0267f5c8d

05 Affected products

VendorProductVersionsPlatforms
n/alibsshlibssh 0.9.6—

06 References

07 Fixed in

AlmaLinux 8

  • libssh
    Fixed in 0.9.6-3.el8
  • libssh-config
    Fixed in 0.9.6-3.el8
  • libssh-devel
    Fixed in 0.9.6-3.el8

Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Arch Linux

  • libssh
    Fixed in 0.9.6-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

CloudLinux 8

  • libssh
    Fixed in 0.9.6-3.el8
  • libssh-config
    Fixed in 0.9.6-3.el8
  • libssh-devel
    Fixed in 0.9.6-3.el8

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.

Debian 12

  • libssh
    Fixed in 0.9.6-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • libssh
    Fixed in 0.9.6-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • libssh
    Fixed in 0.9.6-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

  • libssh
    Fixed in 0.9.3-2ubuntu2.2

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 22.04 LTS

  • libssh
    Fixed in 0.9.6-1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.