DescriptionA vulnerability was found in libssh, where the authentication check of the connecting client can be bypassed in the`pki_verify_data_signature` function in memory allocation problems. This issue may happen if there is insufficient memory or the memory usage is limited. The problem is caused by the return value `rc,` which is initialized to SSH_ERROR and later rewritten to save the return value of the function call `pki_key_check_hash_compatible.` The value of the variable is not changed between this point and the cryptographic verification. Therefore any error between them calls `goto error` returning SSH_OK.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1035832

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libssh (PTS)buster0.8.7-1+deb10u1fixed
buster (security)0.8.7-1+deb10u2fixed
bullseye, bullseye (security)0.9.7-0+deb11u1fixed
sid, trixie0.10.5-3fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libsshsourcebuster(not affected)


[buster] - libssh <not-affected> (Vulnerable code introduced later)
Fixed by: (libssh-0.10.5)
Fixed by: (libssh-0.10.5)
Vulnerable function introduced with: (libssh-0.9.0)

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