PT-2026-31041 · Openssl · Openssl

Nikola Pajkovsky

+1

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Published

2026-04-07

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Updated

2026-04-07

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CVE-2026-31790

None

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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 in place of the KEM ciphertext.
As a workaround calling EVP PKEY public check() or EVP PKEY public check quick() before EVP PKEY encapsulate() will mitigate the issue.
The FIPS modules in 3.6, 3.5, 3.4, 3.3, 3.1 and 3.0 are affected by this issue.

Improper Check for Exceptional Conditions

Weakness Enumeration

Related Identifiers

CVE-2026-31790

Affected Products

Openssl