CVE-2025-15469
Issue summary: The 'openssl dgst' 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 'openssl dgst' 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 'openssl dgst' command. Streaming digest algorithms for 'openssl dgst' 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.
| Software | From | Fixed in |
|---|---|---|
| openssl / openssl | 3.5.0 | 3.5.5 |
| openssl / openssl | 3.6.0 | 3.6.1 |
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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
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