CVE-2024-21491: Versions of the package svix before 1.17.0 are vulnerable to Authentication Bypass due to an issue in the verify function where signatures of...
Description
Versions of the package svix before 1.17.0 are vulnerable to Authentication Bypass due to an issue in the verify function where signatures of different lengths are incorrectly compared. An attacker can bypass signature verification by providing a shorter signature that matches the beginning of the actual signature.
**Note:**
The attacker would need to know a victim uses the Rust library for verification,no easy way to automatically check that; and uses webhooks by a service that uses Svix, and then figure out a way to craft a malicious payload that will actually include all of the correct identifiers needed to trick the receivers to cause actual issues.
Classification
CVE ID: CVE-2024-21491
CVSS Base Severity: MEDIUM
CVSS Base Score: 5.9
CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:N
Problem Types
Authentication BypassAffected Products
Vendor: n/a
Product: svix
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.03% (probability of being exploited)
EPSS Percentile: 5.22% (scored less or equal to compared to others)
EPSS Date: 2025-06-07 (when was this score calculated)
Stakeholder-Specific Vulnerability Categorization (SSVC)
SSVC Exploitation: poc
SSVC Technical Impact: partial
SSVC Automatable: false
References
https://nvd.nist.gov/vuln/detail/CVE-2024-21491https://security.snyk.io/vuln/SNYK-RUST-SVIX-6230729
https://github.com/svix/svix-webhooks/pull/1190
https://github.com/svix/svix-webhooks/commit/958821bd3b956d1436af65f70a0964d4ffb7daf6
https://rustsec.org/advisories/RUSTSEC-2024-0010.html