Bug 2376219 (CVE-2025-5987)

Summary: CVE-2025-5987 libssh: Invalid return code for chacha20 poly1305 with OpenSSL backend
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: adudiak, kshier, omaciel, paul, stcannon, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in libssh when using the ChaCha20 cipher with the OpenSSL library. If an attacker manages to exhaust the heap space, this error is not detected and may lead to libssh using a partially initialized cipher context. This occurs because the OpenSSL error code returned aliases with the SSH_OK code, resulting in libssh not properly detecting the error returned by the OpenSSL library. This issue can lead to undefined behavior, including compromised data confidentiality and integrity or crashes.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2376226, 2376229, 2376223, 2376224, 2376225, 2376227, 2376228    
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Description OSIDB Bzimport 2025-07-03 21:58:14 UTC 
If there is an error in initializing ChaCha20 cipher with OpenSSL, an invalid error code is returned. This can happen if there is an heap exhaustion.  This error is not correctly detected and could allow libssh to use partially
initialized cipher context. This is caused by the mismatch of return value meaning from OpenSSL and libssh, where OpenSSL error (rv=0) aliases with SSH_OK (0) and is returned directly from the function chacha20_poly1305_set_key(). This will likely cause error somewhere down the road.