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Regular Expression Denial of Service in Handlebars

High severity GitHub Reviewed Published Feb 10, 2022 to the GitHub Advisory Database • Updated Nov 29, 2023

Package

npm handlebars (npm)

Affected versions

>= 4.0.0, < 4.4.5

Patched versions

4.4.5

Description

Handlebars before 4.4.5 allows Regular Expression Denial of Service (ReDoS) because of eager matching. The parser may be forced into an endless loop while processing crafted templates. This may allow attackers to exhaust system resources.

References

Published by the National Vulnerability Database Sep 30, 2020
Reviewed Apr 22, 2021
Published to the GitHub Advisory Database Feb 10, 2022
Last updated Nov 29, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.191%
(58th percentile)

Weaknesses

CVE ID

CVE-2019-20922

GHSA ID

GHSA-62gr-4qp9-h98f

Source code

No known source code
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