The vulnerability is a timing side‑channel in the RSA PKCS#1 v1.5 decryption routine of the Oberon PSA Crypto library. It permits an attacker to recover the plaintext of ciphertexts by measuring decryption duration variations caused by padding validation logic. This flaw maps to CWE‑208 (Timing Attack) and CWE‑327 (Improper Use of Cryptographic Primitive). The result is the disclosure of any decrypted data, compromising confidentiality and potentially enabling further attacks.

Affected vendors and products are Oberon microsystems AG and its Oberon PSA Crypto library, in all releases from the initial 1.0.0 through 2.1.0. Systems that use this library for RSA PKCS#1 v1.5 decryption are at risk. The vulnerability affects any deployment that performs these decryption operations.

The CVSS score of 5.9 indicates moderate severity, and the lack of an EPSS value shows no evidence of widespread exploitation yet. The vulnerability is not listed in CISA KEV. The likely attack vector is an attacker who can observe or influence the timing of RSA decryption operations, such as an adversary with local or remote access to the system. Exploitation requires careful timing measurements and is feasible when the attacker can query the decryption API repeatedly. While exploitation probability may be low, the confidentiality impact and the ubiquity of the library justify prompt remediation.