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TI-2026-42663 Aliases CVE-2026-59847GHSA-mq2j-7vq4-77m8

Libssh: libssh: integrity downgrade via openssl aes-gcm tag verification

Priority LOW 39CWE-253Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.

Summary

A flaw was found in libssh. Incorrect AES-GCM finalization checks in builds using the OpenSSL backend can effectively remove integrity protection, allowing an in-path attacker to modify plaintext on the wire without detection.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00332 26th percentileScored 2026-11-07
Fix Fixed Red Hat: 4 advisories

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Red HatRed Hat Enterprise Linux 10—0.12.0-3.el10_2Patch availableCNA
Red HatRed Hat Enterprise Linux 8—0.9.6-17.el8_10Patch availableCNA
Red HatRed Hat Enterprise Linux 8—0.9.6-17.el8_10Patch availableCNA
Red HatRed Hat Enterprise Linux 9—0.10.4-19.el9_8Patch availableCNA
Red HatRed Hat Enterprise Linux 9—0.10.4-19.el9_8Patch availableCNA
Red HatRed Hat Hardened Images—0.12.1-4.hum1Patch availableCNA
  • Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in 0.12.0-3.el10_2 Patch available CNA
  • Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in 0.9.6-17.el8_10 Patch available CNA
  • Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in 0.9.6-17.el8_10 Patch available CNA
  • Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in 0.10.4-19.el9_8 Patch available CNA
  • Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in 0.10.4-19.el9_8 Patch available CNA
  • Red Hat Hardened Images VendorRed Hat Affected — Fixed in 0.12.1-4.hum1 Patch available CNA

CPE configurations NVD · 6

CPEVersionsRoleVendor
cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:*0.9.0 to before 0.11.5Vulnerablelibssh
cpe:2.3:a:libssh:libssh:0.12.0:*:*:*:*:*:*:*0.12.0Vulnerablelibssh
cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*not specified by NVDVulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*8.0VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*9.0VulnerableRed Hat
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*10.0VulnerableRed Hat
  • cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:* Versions 0.9.0 to before 0.11.5 Vulnerable ·libssh
  • cpe:2.3:a:libssh:libssh:0.12.0:*:*:*:*:*:*:* Versions 0.12.0 Vulnerable ·libssh
  • cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* Versions 8.0 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Red Hat
  • cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Red Hat

Remediation

Red Hat 4 advisories

  • RHSA-2026:62218 Released 2026-09-01 · Red Hat rating Moderate
    libssh security update
    • Red Hat Enterprise Linux AppStream (v. 8) libssh-devel-0.9.6-17.el8_10
    • Red Hat Enterprise Linux BaseOS (v. 8) libssh-0.9.6-17.el8_10, libssh-config-0.9.6-17.el8_10
  • RHSA-2026:62217 Released 2026-09-01 · Red Hat rating Moderate
    libssh security update
    • Red Hat Enterprise Linux AppStream (v. 9) libssh-devel-0.10.4-19.el9_8
    • Red Hat Enterprise Linux BaseOS (v. 9) libssh-0.10.4-19.el9_8, libssh-config-0.10.4-19.el9_8
  • RHSA-2026:55855 Released 2026-08-17 · Red Hat rating Important
    libssh security update
    • Red Hat Enterprise Linux AppStream (v. 10) libssh-devel-0.12.0-3.el10_2
    • Red Hat Enterprise Linux BaseOS (v. 10) libssh-0.12.0-3.el10_2, libssh-config-0.12.0-3.el10_2
Show 1 more Red Hat advisories
  • RHSA-2026:42922 Released 2026-07-21 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images libssh-0.12.1-4.hum1@aarch64, libssh-0.12.1-4.hum1@src, libssh-0.12.1-4.hum1@x86_64 +4

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 and 2 more products — RHSA-2026:55855

    11 records Highest priority Priority MEDIUM 1 MEDIUM, 10 LOW

    Other records, highest priority first

    • TI-2026-42667 Libssh: libssh: authentication bypass via missing gssapi principal checkPriority MEDIUM 41
    • TI-2026-42666 Libssh: libssh: use-after-free via data callbacks on closed channelsPriority LOW 33
    • TI-2026-42665 Libssh: libssh: denial of service via automatic certificate authentication loopPriority LOW 33
    Show all 11 records → Advisory →
  • Advisory ·

    Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 and 2 more products — RHSA-2026:42922

    10 records Highest priority Priority MEDIUM 1 MEDIUM, 9 LOW

    Other records, highest priority first

    • TI-2026-42667 Libssh: libssh: authentication bypass via missing gssapi principal checkPriority MEDIUM 41
    • TI-2026-42666 Libssh: libssh: use-after-free via data callbacks on closed channelsPriority LOW 33
    • TI-2026-42665 Libssh: libssh: denial of service via automatic certificate authentication loopPriority LOW 33
    Show all 10 records → Advisory →
Show 2 more groups
  • Advisory ·

    Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 and 2 more products — RHSA-2026:62217

    7 records Highest priority Priority LOW 7 LOW

    Other records, highest priority first

    • TI-2026-42666 Libssh: libssh: use-after-free via data callbacks on closed channelsPriority LOW 33
    • TI-2026-42664 Libssh: libssh: denial of service via sftp responses with unknown request idsPriority LOW 30
    • TI-2026-42660 Libssh: libssh: denial of service via oversized sftp read lengthPriority LOW 30
    Show all 7 records → Advisory →
  • Advisory ·

    Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8 and 2 more products — RHSA-2026:62218

    7 records Highest priority Priority LOW 7 LOW

    Other records, highest priority first

    • TI-2026-42666 Libssh: libssh: use-after-free via data callbacks on closed channelsPriority LOW 33
    • TI-2026-42664 Libssh: libssh: denial of service via sftp responses with unknown request idsPriority LOW 30
    • TI-2026-42660 Libssh: libssh: denial of service via oversized sftp read lengthPriority LOW 30
    Show all 7 records → Advisory →

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:55855
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:62218
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:62217
Red Hat Enterprise Linux BaseOS (v. 10)Fixed RHSA-2026:55855
Red Hat Enterprise Linux BaseOS (v. 8)Fixed RHSA-2026:62218
Red Hat Enterprise Linux BaseOS (v. 9)Fixed RHSA-2026:62217
Red Hat Hardened ImagesFixed RHSA-2026:42922

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-59847
  2. 2026-10-03 Alias added: GHSA-mq2j-7vq4-77m8

References

Advisory 6

  • TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2018-10530 Code injection in [UNKNOWN] RichFaces KEVCVSS 3.1CRITICAL 9.8
  • TI-2014-05975 GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed… KEVCVSS 3.1CRITICAL 9.8
  • TI-2014-05157 GNU Bash through 4.3 processes trailing strings after function definitions in the values… KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-23530 Sudo before 1.9.17p1 allows local users to obtain root access because /etc/nsswitch.conf… KEVCVSS 3.1CRITICAL 9.3
  • TI-2021-17490 mod_proxy SSRF KEVCVSS 3.1CRITICAL 9.0
See all 1955 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences