The vulnerability arises from CipherCtxRef::cipher_update_inplace in rust‑openssl incorrectly sizing output buffers for AES key‑wrap‑with‑padding ciphers. When the plaintext is not a multiple of eight, OpenSSL copies up to seven bytes past the end of the caller’s buffer or Vec, producing attacker‑controlled heap corruption when the plaintext length is attacker‑influenced. This flaw manifests as a classic buffer overflow and integer overflow error (CWE‑131, CWE‑787).

The affected product is the Rust OpenSSL bindings crate rust‑openssl. Versions from 0.10.50 up through 0.10.79 contain the flaw; the issue is fixed in version 0.10.80 and later.

The CVSS score of 5.1 indicates moderate severity, while an EPSS score of less than 1% suggests a low probability of exploitation at this time. The vulnerability is not listed in the CISA KEV catalog. The likely attack vector is a local compromise where an application that uses the vulnerable AES key‑wrap‑with‑padding cipher operations can supply attacker‑controlled plaintext. Because the flaw is a heap out‑of‑bounds write, successful exploitation could achieve arbitrary code execution if the attacker can manipulate the memory layout, but such exploitation requires precise conditions and is therefore considered less likely.