CVE-2026-31790

Technical Description

Issue summary: Applications using RSASVE key encapsulation to establish

a secret encryption key can send contents of an uninitialized memory buffer to

a malicious peer.

Impact summary: The uninitialized buffer might contain sensitive data from the

previous execution of the application process which leads to sensitive data

leakage to an attacker.

RSA_public_encrypt() returns the number of bytes written on success and -1

on error. The affected code tests only whether the return value is non-zero.

As a result, if RSA encryption fails, encapsulation can still return success to

the caller, set the output lengths, and leave the caller to use the contents of

the ciphertext buffer as if a valid KEM ciphertext had been produced.

If applications use EVP_PKEY_encapsulate() with RSA/RSASVE on an

attacker-supplied invalid RSA public key without first validating that key,

then this may cause stale or uninitialized contents of the caller-provided

ciphertext buffer to be disclosed to the attacker i

Remediation

Check the references section for vendor advisories and patches from openssl. Update openssl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References