CVE-2026-59842

Libssh: libssh: information disclosure via short gssapi curve25519 public key

Published Jul 21, 2026 CVSS 3.1 · 3.7 Low EPSS < 1% KEV · Not listed
Description
A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.

Remediation

Vendor Workaround

Disable GSSAPIKeyExchange or remove gss-curve25519-sha256- from GSSAPIKexAlgorithms if appropriate.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
cpe:/a:redhat:enterprise_linux:8
cpe:/a:redhat:enterprise_linux:9
Type Values Removed Values Added
First Time appeared Redhat enterprise Linux For Els
Redhat enterprise Linux For Eus
Redhat enterprise Linux For Ibm Z Systems
Redhat enterprise Linux For Ibm Z Systems Els
Redhat enterprise Linux For Ibm Z Systems Eus
Redhat enterprise Linux For Power Little Endian
Redhat enterprise Linux For Power Little Endian Els
Redhat enterprise Linux For Power Little Endian Eus
CPEs cpe:2.3:a:libssh:libssh:-:*:*:*:*:*:*:* cpe:2.3:a:libssh:libssh:0.12.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:x64:*
cpe:2.3:o:redhat:enterprise_linux:10.2:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux:10.2:*:*:*:*:*:x64:*
cpe:2.3:o:redhat:enterprise_linux_for_els:10.2:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux_for_els:10.2:*:*:*:*:*:x64:*
cpe:2.3:o:redhat:enterprise_linux_for_eus:10.2:*:*:*:*:*:arm64:*
cpe:2.3:o:redhat:enterprise_linux_for_eus:10.2:*:*:*:*:*:x64:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:10.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_els:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:10.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_els:10.2:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:10.2:*:*:*:*:*:*:*
Vendors & Products Redhat enterprise Linux For Els
Redhat enterprise Linux For Eus
Redhat enterprise Linux For Ibm Z Systems
Redhat enterprise Linux For Ibm Z Systems Els
Redhat enterprise Linux For Ibm Z Systems Eus
Redhat enterprise Linux For Power Little Endian
Redhat enterprise Linux For Power Little Endian Els
Redhat enterprise Linux For Power Little Endian Eus
Type Values Removed Values Added
CPEs cpe:/o:redhat:enterprise_linux:10 cpe:/o:redhat:enterprise_linux:10.2
References
Type Values Removed Values Added
First Time appeared Libssh
Libssh libssh
Redhat hardened Images
Vendors & Products Libssh
Libssh libssh
Redhat hardened Images
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.
Title Libssh: libssh: information disclosure via short gssapi curve25519 public key
First Time appeared Redhat
Redhat enterprise Linux
Redhat hummingbird
Weaknesses CWE-125
CPEs cpe:/a:redhat:hummingbird:1
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat hummingbird
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}