CVE-2026-81721
HIGHCVE-2026-81721 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability. O3 Security confirms whether CVE-2026-81721 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
openssl_encrypt before 1.4.9 fails to validate KDF cost parameters in encrypted file metadata and keystore headers, allowing attackers to trigger unbounded memory allocation. Attackers…
Description
openssl_encrypt before 1.4.9 fails to validate KDF cost parameters in encrypted file metadata and keystore headers, allowing attackers to trigger unbounded memory allocation. Attackers can craft malicious encrypted files declaring arbitrarily large Argon2, scrypt, or balloon KDF parameters to exhaust system memory and crash the process without authentication.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-81721 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-81721 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-81721. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-81721 in your dependencies?
O3 detects CVE-2026-81721 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.