OpenSSL Improper Verification of Cryptographic Signature Vulnerability - CVE-2025-15469

Issue summary: The 39openssl dgst39 command-line tool silently truncates input data to 16MB when using one-shot signing algorithms and reports success instead of an error. Impact summary: A user signing or verifying files larger than 16MB with one-shot algorithms (such as Ed25519 Ed448 or ML-DSA) may believe the entire file is authenticated while trailing data beyond 16MB remains unauthenticated. When the 39openssl dgst39 command is used with algorithms that only support one-shot signing (Ed25519 Ed448 ML-DSA-44 ML-DSA-65 ML-DSA-87) the input is buffered with a 16MB limit. If the input exceeds this limit the tool silently truncates to the first 16MB and continues without signaling an error contrary to what the documentation states. This creates an integrity gap where trailing bytes can be modified without detection if both signing and verification are performed using the same affected codepath. The issue affects only the command-line tool behavior. Verifiers that process the full message using library APIs will reject the signature so the risk primarily affects workflows that both sign and verify with the affected 39openssl dgst39 command. Streaming digest algorithms for 39openssl dgst39 and library users are unaffected. The FIPS modules in 3.5 and 3.6 are not affected by this issue as the command-line tools are outside the OpenSSL FIPS module boundary. OpenSSL 3.5 and 3.6 are vulnerable to this issue. OpenSSL 3.4 3.3 3.0 1.1.1 and 1.0.2 are not affected by this issue.