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Non-constant time HMAC comparison

Moderate severity GitHub Reviewed Published May 24, 2022 to the GitHub Advisory Database • Updated Dec 13, 2023

Package

maven org.jenkins-ci.main:jenkins-core (Maven)

Affected versions

<= 2.204.1
>= 2.205, <= 2.218

Patched versions

2.204.2
2.219

Description

Jenkins 2.218 and earlier, LTS 2.204.1 and earlier does not use a constant-time comparison when checking whether two HMACs are equal. This could potentially allow attackers to use statistical methods to obtain a valid HMAC for an attacker-controlled input value.

Jenkins 2.219, LTS 2.204.2 now uses a constant-time comparison when validating HMACs.

References

Published by the National Vulnerability Database Jan 29, 2020
Published to the GitHub Advisory Database May 24, 2022
Reviewed Dec 19, 2022
Last updated Dec 13, 2023

Severity

Moderate
5.3
/ 10

CVSS base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Weaknesses

CVE ID

CVE-2020-2102

GHSA ID

GHSA-fj6f-6933-839j

Source code

Credits

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