CVE-2024-21491

MEDIUM
6.5
CVSS Score
Published: February 13, 2024 at 05:00 AM UTC
Updated: June 17, 2026 at 07:09 AM UTC
1 product affected across 1 vendorSvix Webhooks

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.4%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.17.0
Affected range stops below 1.17.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-288CWE-347

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