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JenkinsApplication

CVE-2020-2102

MEDIUM · 5.3 CVSS v3.1 Published 2020-01-29
Fix available
A fix is available. Upgrade to after 2.218 or later.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Jenkins 2.218 and earlier, LTS 2.204.1 and earlier used a non-constant time comparison function when validating an HMAC.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Jenkins versions 2.218 and earlier, LTS 2.204.1 and earlier used a non-constant time comparison function when validating HMAC (Hash-based Message Authentication Code) values. This timing side-channel could allow an attacker to infer information about the HMAC by measuring response times, potentially enabling forgery of authentication tokens through byte-by-byte timing attacks.

MitigationUpgrade to Jenkins 2.218.1 or later, or Jenkins LTS 2.204.2 or later, which implement constant-time HMAC comparison.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JenkinsApplication
Affected:<= 2.204.1<= 2.218

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Find installed Jenkins version
    Access the Jenkins web UI and go to Manage Jenkins > About Jenkins, or query the API at http://your-jenkins/api/json?tree=version, or run 'java -jar jenkins.war --version' from the server
    Affected if Unable to retrieve a version number or version shows as unknown
  2. Confirm if running LTS release
    If version is visible, check if it is an LTS (Long Term Support) release by noting the version format (LTS versions typically lack the decimal in the second number like 2.204.x)
    Affected if Version format cannot be determined as LTS or weekly
  3. Compare version against affected ranges
    For LTS releases, compare against <= 2.204.1. For weekly releases, compare against <= 2.218. Note that version 2.204.2 and later, and 2.218.1 and later, are NOT affected
    Affected if Version is 2.204.1 or earlier (LTS), or 2.218 or earlier (weekly)

A user is affected if their Jenkins installation shows a version number at or below 2.204.1 for LTS releases, or at or below 2.218 for weekly releases, since those versions contain the non-constant time HMAC comparison function.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 2.218
Interim mitigation

Upgrade to Jenkins 2.218.1 or later, or Jenkins LTS 2.204.2 or later, which implement constant-time HMAC comparison.

Fix this in Jenkins Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-2102 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data