CVE-2025-12816

What it actually does

This vulnerability is an ASN.1 parsing and interpretation conflict in node-forge 1.3.1 and earlier. A remote unauthenticated attacker can craft ASN.1-encoded structures that are interpreted differently by validation logic and downstream cryptographic decision logic. That semantic mismatch can cause a malformed or deceptive certificate, signature, key, or other ASN.1-backed object to pass checks it should fail, potentially bypassing signature verification, certificate validation, or other trust decisions in software that relies on vulnerable node-forge behavior. In affected downstream packages such as cosign-fips, the practical impact depends on how ASN.1 parsing results are used in verification workflows.

Why it matters to the business

Systems that rely on affected cryptographic verification may make incorrect trust decisions, such as accepting an artifact, certificate, or signature that should be rejected. For organizations using affected supply-chain security tooling, this can weaken controls intended to prove software authenticity and integrity. Although the issue is not currently listed in CISA KEV, has low EPSS, and has no public exploit maturity reported, the high CVSS score and cryptographic bypass nature make it important to remediate in verification-sensitive environments.

How an attack unfolds

An attacker identifies an application or security workflow that processes attacker-controlled ASN.1 data through a vulnerable node-forge version or an affected downstream package. The attacker then crafts an ASN.1 structure designed to create a mismatch between schema validation and the later cryptographic or policy decision. If the target accepts the malformed structure, the validation layer may treat it as acceptable while the downstream logic interprets the same bytes differently or trusts fields that were not validated as intended. In a vulnerable verification path, this can result in a forged, malformed, or policy-violating cryptographic object being accepted as valid. The provided threat context references a Forge ASN.1 signature verification bypass, but no named APT group or ransomware use is currently indicated.

How to fix it

Upgrade affected packages to fixed versions. For Chainguard cosign-fips, upgrade to version 2.3.0-r1 or later. Where node-forge is used directly, ensure node-forge is updated beyond vulnerable versions 1.3.1 and below once a fixed release is available in the relevant package ecosystem. Rebuild and redeploy applications or containers that vendor or bundle vulnerable dependencies. Regenerate software bills of materials and re-run dependency scans after upgrading. If immediate upgrade is not possible, reduce exposure by rejecting untrusted ASN.1 inputs where feasible, enforcing strict certificate/signature validation with independent libraries, adding allowlists for trusted issuers or signing identities, and isolating verification workflows from untrusted network paths.

How to confirm the fix worked

Confirm that deployed packages no longer include node-forge 1.3.1 or below and that cosign-fips is at 2.3.0-r1 or later where applicable. Use package manager inventory, SBOM tooling, container image scans, and lockfile review to verify effective versions in both build-time and runtime artifacts. Rebuild from clean dependency caches to avoid stale vendored copies. Run regression tests using valid and intentionally malformed ASN.1 certificates, signatures, and keys to confirm malformed objects are rejected. Validate that CI/CD or artifact-verification workflows fail closed when parsing or verification errors occur.

Typical attack path

1. Identify a service, application, CI/CD workflow, artifact verification process, or security tool using vulnerable node-forge ASN.1 parsing behavior.
2. Determine whether attacker-controlled certificates, signatures, keys, CSRs, tokens, signed artifacts, or other ASN.1-encoded data are accepted by that workflow.
3. Craft an ASN.1 payload that creates a semantic difference between schema validation and downstream verification logic.
4. Submit the crafted object to the vulnerable verification path remotely without authentication, where applicable.
5. Cause the target to accept a cryptographic object, signature, or trust decision that should have failed validation.
6. Use the bypass to weaken integrity guarantees, impersonate trust relationships, or introduce untrusted artifacts into a process that relies on successful verification.

How to detect it

Retrospective detection is difficult because successful exploitation may look like a normal verification success rather than a crash or obvious error. Review logs from applications, CI/CD systems, artifact registries, signing and verification tools, certificate-processing services, and API endpoints that accept certificates, signatures, CSRs, public keys, or signed artifacts. Look for unusual ASN.1 parsing errors, verification retries, malformed certificate or signature submissions followed by successful acceptance, newly trusted signing identities, unexpected certificate chains, or artifacts accepted from untrusted sources. Compare historical accepted artifacts against stricter patched verification to identify objects that now fail validation. Preserve suspicious certificates, signatures, signed bundles, and request bodies for offline ASN.1 inspection. If using cosign-fips in build or deployment workflows, review verification logs around artifact promotion and release events for unexpected successes, policy overrides, or fallback behavior.

What your security team should do

• Prioritize upgrading cosign-fips to 2.3.0-r1 or later in environments where software signing, artifact verification, certificate validation, or release integrity controls depend on it.
• Inventory direct and transitive node-forge usage across applications, containers, build systems, and security tooling, paying special attention to versions 1.3.1 and below.
• Review verification workflows that consume untrusted ASN.1 data, including certificates, signatures, CSRs, keys, and signed software artifacts.
• Add negative test cases for malformed ASN.1 inputs to cryptographic verification pipelines and ensure failures are logged and fail closed.
• Monitor vendor advisories for node-forge and downstream packages because exploitability depends heavily on how the library is used by the consuming product.
• Treat unexpected verification success for malformed or unusual ASN.1 structures as a security event and investigate associated artifacts.
• Because the issue is not currently KEV-listed and EPSS is low, balance urgency against exposure, but remediate promptly in high-trust or supply-chain-sensitive workflows.