Openssl · Openssl · CVE-2026-31790
**Name of the Vulnerable Software and Affected Versions**
OpenSSL FIPS modules versions 3.0 through 3.6
**Description**
Applications using RSASVE key encapsulation can send contents of an uninitialized memory buffer to a malicious peer, potentially leading to sensitive data leakage. This occurs when applications use `EVP PKEY encapsulate()` with RSA/RSASVE on an attacker-supplied invalid RSA public key without first validating that key. The `RSA public encrypt()` function returns the number of bytes written on success and -1 on error, but the affected code only checks if the return value is non-zero. If RSA encryption fails, the encapsulation can still return success, allowing the caller to use uninitialized ciphertext. Calling `EVP PKEY public check()` or `EVP PKEY public check quick()` before `EVP PKEY encapsulate()` can mitigate this issue.
**Recommendations**
Apply the OpenSSL April 2026 security update immediately.
If you cannot update immediately, call `EVP PKEY public check()` or `EVP PKEY public check quick()` before `EVP PKEY encapsulate()` as a mitigation.
Audit uses of RSASVE/`EVP PKEY encapsulate()` and ensure public keys are validated prior to encapsulation.
Rotate keys/secrets if exposure is suspected.