CVE-2026-33746

Convoy: JWT Signature Verification Bypass Allows Authentication as Arbitrary Users

Published Apr 2, 2026 CVSS 3.1 · 9.8 Critical EPSS < 1% KEV · Not listed
Description
Convoy is a KVM server management panel for hosting businesses. From version 3.9.0-beta to before version 4.5.1, the JWTService::decode() method did not verify the cryptographic signature of JWT tokens. While the method configured a symmetric HMAC-SHA256 signer via lcobucci/jwt, it only validated time-based claims (exp, nbf, iat) using the StrictValidAt constraint. The SignedWith constraint was not included in the validation step. This means an attacker could forge or tamper with JWT token payloads — such as modifying the user_uuid claim — and the token would be accepted as valid, as long as the time-based claims were satisfied. This directly impacts the SSO authentication flow (LoginController::authorizeToken), allowing an attacker to authenticate as any user by crafting a token with an arbitrary user_uuid. This issue has been patched in version 4.5.1.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Convoypanel convoy
CPEs cpe:2.3:a:convoypanel:convoy:*:*:*:*:*:*:*:*
Vendors & Products Convoypanel convoy
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Convoypanel
Convoypanel panel
Vendors & Products Convoypanel
Convoypanel panel
Type Values Removed Values Added
Description Convoy is a KVM server management panel for hosting businesses. From version 3.9.0-beta to before version 4.5.1, the JWTService::decode() method did not verify the cryptographic signature of JWT tokens. While the method configured a symmetric HMAC-SHA256 signer via lcobucci/jwt, it only validated time-based claims (exp, nbf, iat) using the StrictValidAt constraint. The SignedWith constraint was not included in the validation step. This means an attacker could forge or tamper with JWT token payloads — such as modifying the user_uuid claim — and the token would be accepted as valid, as long as the time-based claims were satisfied. This directly impacts the SSO authentication flow (LoginController::authorizeToken), allowing an attacker to authenticate as any user by crafting a token with an arbitrary user_uuid. This issue has been patched in version 4.5.1.
Title Convoy: JWT Signature Verification Bypass Allows Authentication as Arbitrary Users
Weaknesses CWE-287
CWE-347
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Apr 2, 2026, 6:50 PM
Reserved
Mar 23, 2026, 6:30 PM
Status
Analyzed
Published
Apr 2, 2026, 4:16 PM
Modified
Jul 24, 2026, 9:10 PM