How severe is GHSA-3prj-6hqw-cm82?

No CVSS score has been assigned to GHSA-3prj-6hqw-cm82 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-3prj-6hqw-cm82?

GHSA-3prj-6hqw-cm82 affects the following packages: web-token/jwt-library (Packagist), web-token/jwt-framework (Packagist), web-token/jwt-library (Packagist), web-token/jwt-library (Packagist), web-token/jwt-framework (Packagist), web-token/jwt-framework (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-3prj-6hqw-cm82?

Update web-token/jwt-library to 3.4.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3prj-6hqw-cm82 is resolved across your whole dependency graph.

How do I detect GHSA-3prj-6hqw-cm82 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for web-token/jwt-library, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-3prj-6hqw-cm82 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-3prj-6hqw-cm82 actively exploited in the wild?

No public exploit code has been indexed for GHSA-3prj-6hqw-cm82 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-3prj-6hqw-cm82 published, and has it been updated?

GHSA-3prj-6hqw-cm82 was published on June 18, 2026 and was last updated on July 15, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

PHP JWT Library: PBES2-HS+AKW unwrap accepts an unbounded p2c iteration count, enabling CPU-amplification denial of serviceGHSA-3prj-6hqw-cm82

GHSA-3prj-6hqw-cm82 is a security vulnerability in web-token/jwt-library. A fix is available for web-token/jwt-library — see the affected versions and patch details below.

Published

Jun 18, 2026

Updated

Jul 15, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

None indexed

Exploitation data as of Jul 15, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

6 pkgs affected

🐘web-token/jwt-library🐘web-token/jwt-framework🐘web-token/jwt-library🐘web-token/jwt-library🐘web-token/jwt-framework🐘web-token/jwt-framework

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Impact

When a JWE uses a password-based key-encryption algorithm (PBES2-HS256+A128KW, PBES2-HS384+A192KW, PBES2-HS512+A256KW), PBES2AESKW::unwrapKey() reads the p2c (PBKDF2 iteration count) parameter directly from the attacker-controlled JOSE header and passes it to hash_pbkdf2() with no upper bound. The only validation performed (checkHeaderAdditionalParameters()) was is_int($p2c) && $p2c > 0.

An unauthenticated attacker can craft a single JWE whose protected header sets a very large p2c (e.g. 100_000_000 ≈ 87 s of CPU, or PHP_INT_MAX), forcing a worker to spend an arbitrary amount of CPU inside PBKDF2 before the key unwrap can even fail. The decrypter swallows the eventual exception, so the attacker pays almost nothing while the server burns CPU. JSON General serialization (multiple recipients) and multi-key JWKSets multiply the cost. This is a classic uncontrolled-resource-consumption (CWE-400) denial of service.

Affected configurations

Applications that register any PBES2-HS*+A*KW algorithm in their decryption AlgorithmManager.

Patches

PBES2AESKW now enforces a configurable maximum iteration count (DEFAULT_MAX_COUNT = 1_000_000, well above realistic legitimate values which are a few thousand) in checkHeaderAdditionalParameters(), before any PBKDF2 computation. The bound is exposed as a constructor argument so operators can tune it.

Workarounds

Before upgrading: validate/limit the p2c header with a custom header checker, or do not enable PBES2 algorithms for untrusted tokens.

References

RFC 7518 §4.8 (PBES2)
CWE-400: Uncontrolled Resource Consumption

Résolution

Un correctif a été préparé sur une branche dédiée basée sur 3.4.x, avec des tests anti-régression dédiés (fork privé temporaire de cette advisory, PR #1).

PBES2 — PBES2AESKW::unwrapKey() borne désormais le paramètre p2c (constante DEFAULT_MAX_COUNT = 1_000_000, configurable via le constructeur) avant tout appel à hash_pbkdf2(), empêchant l'amplification CPU (DoS).

Validation : php -l OK, PHPUnit vert, aucune nouvelle erreur PHPStan introduite (différentiel nul vs 3.4.x), aucun commentaire ajouté dans le code source. Après merge, cascade prévue 3.4.x → 4.0.x → 4.1.x.

Affected Packages

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`web-token/jwt-library`	all versions	3.4.10`composer require web-token/jwt-library:^3.4.10`
🐘Packagist	`web-token/jwt-framework`	all versions	3.4.10`composer require web-token/jwt-framework:^3.4.10`
🐘Packagist	`web-token/jwt-library`	≥ 4.0.0&&< 4.0.7	4.0.7`composer require web-token/jwt-library:^4.0.7`
🐘Packagist	`web-token/jwt-library`	≥ 4.1.0&&< 4.1.7	4.1.7`composer require web-token/jwt-library:^4.1.7`
🐘Packagist	`web-token/jwt-framework`	≥ 4.0.0&&< 4.0.7	4.0.7`composer require web-token/jwt-framework:^4.0.7`
🐘Packagist	`web-token/jwt-framework`	≥ 4.1.0&&< 4.1.7	4.1.7`composer require web-token/jwt-framework:^4.1.7`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for web-token/jwt-library, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update web-token/jwt-library to 3.4.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-3prj-6hqw-cm82 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### Impact When a JWE uses a password-based key-encryption algorithm (`PBES2-HS256+A128KW`, `PBES2-HS384+A192KW`, `PBES2-HS512+A256KW`), `PBES2AESKW::unwrapKey()` reads the `p2c` (PBKDF2 iteration count) parameter directly from the attacker-controlled JOSE header and passes it to `hash_pbkdf2()` with **no upper bound**. The only validation performed (`checkHeaderAdditionalParameters()`) was `is_int($p2c) && $p2c > 0`. An unauthenticated attacker can craft a single JWE whose protected header sets a very large `p2c` (e.g. `100_000_000` ≈ 87 s of CPU, or `PHP_INT_MAX`), forcing a worker to spen

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PHP JWT Library: PBES2-HS*+A*KW unwrap accepts an unbounded p2c iteration count, enabling CPU-amplification denial of serviceGHSA-3prj-6hqw-cm82

Real-World Exposure

Description

Impact

Affected configurations

Patches

Workarounds

References

Résolution

Affected Packages

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is GHSA-3prj-6hqw-cm82 in your dependencies?

PHP JWT Library: PBES2-HS+AKW unwrap accepts an unbounded p2c iteration count, enabling CPU-amplification denial of serviceGHSA-3prj-6hqw-cm82