CVE-2024-21491

CVE-2024-21491 is a medium-severity vulnerability in Svix Svix-webhooks with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

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.

Frequently asked questions

What is 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 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.
How severe is CVE-2024-21491?
CVE-2024-21491 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2024-21491 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-21491?
CVE-2024-21491 affects Svix Svix-webhooks. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-21491?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-21491 have an EU (EUVD) identifier?
Yes. CVE-2024-21491 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-0546.
When was CVE-2024-21491 published?
CVE-2024-21491 was published on 2024-02-13 and last updated on 2026-06-17.

References

Affected products (1)

Other CWE-347 (Improper Verification of Cryptographic Signature) vulnerabilities

Browse all CWE-347 (Improper Verification of Cryptographic Signature) vulnerabilities →