# CVE-2026-53776: Perry < 0.5.1166 JWT Expiration Bypass via verify_decode

> Attackers can bypass JWT expiration checks in Perry library to retain authenticated access indefinitely using expired tokens.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 16 Jun 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-5324-c68v-8w62

## What is CVE-2026-53776?

CVE-2026-53776 is a critical authentication bypass vulnerability in PerryTS perry, published on 16 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Perry before 0.5.1166 contains a JWT validation vulnerability that allows remote attackers to bypass token expiration by exploiting the unconditional setting of validate_exp = false in the verify_decode helper within the stdlib JWT verification path. Attackers in possession of a previously issued bearer token can present expired tokens to any jwt.verify() call and retain authenticated access indefinitely, bypassing force-expired sessions such as user logout or administrative revocation.

Weakness: CWE-613 (DEPRECATED: Insufficient Session Expiration)

## Which versions are affected by CVE-2026-53776?


## How do I fix CVE-2026-53776?

No fix has been published for CVE-2026-53776 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53776 being exploited?

There is no known exploitation of CVE-2026-53776 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53776 and fix it if it is affected.

What it is: CVE-2026-53776 is a critical authentication bypass vulnerability in PerryTS perry, published on 16 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-53776 in the wild and no public exploit code.

Affected product: PerryTS perry. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53776/ (Markdown: https://insights.sbomify.com/CVE-2026-53776/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53776
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53776
- OSV: https://osv.dev/vulnerability/CVE-2026-53776

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53776/
Summaries are generated and may contain mistakes; the official description above is the record.