CVE-2026-53431
CVE-2026-53431 is a CWE-294 vulnerability. O3 Security confirms whether CVE-2026-53431 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Authentication Bypass by Capture-replay vulnerability in malach-it Boruta allows an attacker who has obtained a previously valid JWT client assertion to authenticate as the issuing…
Description
Authentication Bypass by Capture-replay vulnerability in malach-it Boruta allows an attacker who has obtained a previously valid JWT client assertion to authenticate as the issuing OAuth client after the assertion has expired.
Boruta accepts JWT-based client authentication (client_secret_jwt and private_key_jwt token endpoint authentication methods) but never enforces that the assertion's exp claim is in the future. The pre-check helper Boruta.Oauth.Request.Base.check_expiration/1 in lib/boruta/oauth/request/base.ex only verifies that an exp claim is present (it pattern-matches on the existence of the key and returns success), and the Joken token configuration used for signature verification, Boruta.Oauth.Authorization.Client.Token.token_config/0 in lib/boruta/oauth/authorization/client.ex, returns an empty map, so Joken's default exp claim validator is not engaged either. Any attacker who obtains a validly-signed client assertion (for example through logs, reverse proxies, browser tooling, or other observability surfaces) can replay it indefinitely to authenticate as the client and obtain access tokens with that client's privileges.
This issue affects boruta: from 2.3.0 before 2.3.7.
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-2026-53431 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-2026-53431 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-2026-53431. 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-2026-53431 in your dependencies?
O3 detects CVE-2026-53431 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.