Converting an excessively large OCTET STRING from an X.509 certificate to a hexadecimal string uses the input length multiplied by three. On 32‑bit platforms this multiplication can overflow, causing an undersized buffer to be allocated on the heap. When extensions such as the Subject Key Identifier or Authority Key Identifier contain such a large value, the resulting buffer overflow may terminate the process or, under specific attacker‑controlled conditions, trigger arbitrary code execution. The vulnerability is tied to the X.509 conversion routine and only manifests when an unusually large extension is supplied.

All OpenSSL distributions that compile the affected X.509 conversion code for 32‑bit architectures are vulnerable. The FIPS modules in versions 3.0 through 3.6 are not affected because the corrupted code lies outside the FIPS boundary. Exact version numbers are not listed in the advisory, so any release preceding the patch commits referenced in the advisory is considered at risk.

The CVSS score of 9.8 indicates critical severity, while the EPSS score of less than 1% suggests a very low likelihood of exploitation in the wild. The vulnerability is not catalogued in CISA’s KEV list, further supporting its low risk profile. Exploitation would require an attacker to supply an X.509 certificate with an OCTET STRING over 1 GB, a scenario inferred from the description and unlikely under normal operation. Consequently the risk of inadvertent or malicious exploitation is minimal but the presence of a heap overflow warrants remediation.