How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.

358,842

Total vulnerabilities in the database

PHP JWT Framework: Chacha20Poly1305 key-encryption algorithm discards the Poly1305 authentication tag, performing no authentication on decryption — web-token / jwt-experimental

Improper Verification of Cryptographic Signature

Impact

The experimental Chacha20Poly1305 key-encryption algorithm generates the 16-byte Poly1305 authentication tag during encryptKey() but discards it: the tag is never written to the header and therefore never reaches the wire. On the receiving side, decryptKey() calls openssl_decrypt('chacha20-poly1305', ...) without the tag argument, which makes OpenSSL skip authentication entirely.

As a result the AEAD construction is silently degraded to unauthenticated ChaCha20: a tampered encrypted CEK is accepted, and because ChaCha20 is a stream cipher, a single-byte change in the ciphertext propagates as a single-byte change in the recovered CEK with no integrity check (CWE-353 / CWE-347). An attacker on the token path can manipulate the wrapped key without detection.

Affected configurations

Applications that register Jose\Experimental\KeyEncryption\Chacha20Poly1305 (package web-token/jwt-experimental) as a JWE alg.

Patches

encryptKey() now publishes the Poly1305 tag as the base64url tag header parameter (and asserts it is 16 bytes). decryptKey() requires the tag header, validates its length, and passes it to openssl_decrypt() so the tag is actually verified, in line with RFC 7539 / RFC 8439. Tampering now results in a decryption failure.

> Note: this changes the wire format of tokens produced with this experimental algorithm (a tag header is now emitted and required).

Workarounds

Do not use the experimental Chacha20Poly1305 key-encryption algorithm for untrusted input until upgraded.

References

RFC 7539 / RFC 8439 (ChaCha20-Poly1305 AEAD)
CWE-353: Missing Support for Integrity Check

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).

ChaCha20-Poly1305 — le tag d'authentification Poly1305 est désormais publié dans le header au chiffrement et vérifié au déchiffrement (RFC 7539), rétablissant l'intégrité AEAD.

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.

Published: Jun 18, 2026
Updated: Jun 19, 2026
GHSA: GHSA-6vvh-pxr4-25r7
Severity: Medium
Exploit:
CISA KEV:

No technical information available.

CWEs:

Affected Software
References

Software	From	Fixed in
web-token / jwt-experimental	-	4.1.6.x
web-token / jwt-library	-	3.4.10
web-token / jwt-library	4.0.0	4.0.7
web-token / jwt-library	4.1.0	4.1.7

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.