CVE-2026-59842 PUBLISHED

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

Assigner: redhat
Reserved: 07.07.2026 Published: 21.07.2026 Updated: 21.07.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS Score: 3.7

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	Red Hat
Product	Red Hat Enterprise Linux 10
Versions	Default: affected

Vendor	Red Hat
Product	Red Hat Enterprise Linux 8
Versions	Default: unaffected

Vendor	Red Hat
Product	Red Hat Enterprise Linux 9
Versions	Default: unaffected

Vendor	Red Hat
Product	Red Hat Hardened Images
Versions	Default: affected

Workarounds

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

Credits

Red Hat would like to thank Haruki Oyama, Yi Lin, and nevv for reporting this issue.

References

Problem Types

Out-of-bounds Read CWE