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PulsarApplication · Apache

CVE-2023-51437

HIGH · 7.4 CVSS v3.1 Published 2024-02-07
Fix available
A fix is available. Upgrade to 2.11.3 / 3.0.2 or later.
See remediation →
83/100
Remediation priority · High
Remotely reachable No privileges 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
Observable timing discrepancy vulnerability in Apache Pulsar SASL Authentication Provider can allow an attacker to forge a SASL Role Token that will pass signature verification. Users are recommended to upgrade to version 2.11.3, 3.0.2, or 3.1.1 which fixes the issue. Users should also consider updating the configured secret in the `saslJaasServerRoleTokenSignerSecretPath` file. Any component matching an above version running the SASL Authentication Provider is affected. That includes the Pulsar Broker, Proxy, Websocket Proxy, or Function Worker. 2.11 Pulsar users should upgrade to at least 2.11.3. 3.0 Pulsar users should upgrade to at least 3.0.2. 3.1 Pulsar users should upgrade to at least 3.1.1. Any users running Pulsar 2.8, 2.9, 2.10, and earlier should upgrade to one of the above patched versions. For additional details on this attack vector, please refer to https://codahale.com/a-lesson-in-timing-attacks/ .

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

This is a timing attack vulnerability in Apache Pulsar's SASL Authentication Provider. The system exhibits observable timing discrepancies during SASL Role Token signature verification, allowing attackers to iteratively guess token signatures until they pass validation. This enables authentication bypass through forged tokens.

MitigationUpgrade Apache Pulsar to version 2.11.3, 3.0.2, or 3.1.1 (depending on your release line) and rotate the secret configured in saslJaasServerRoleTokenSignerSecretPath.

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
PulsarApplication
Affected:<= 2.10.5>= 2.11.0, < 2.11.3>= 3.0.0, < 3.0.2= 3.1.0

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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. Check installed Apache Pulsar version
    Run 'pulsar version' command or inspect the pulsar-core or pulsar-server JAR file version in your deployment
    Affected if Version is <= 2.10.5, or >= 2.11.0 and < 2.11.3, or >= 3.0.0 and < 3.0.2, or exactly 3.1.0
  2. Verify SASL authentication is enabled
    Examine pulsar.conf or standalone.conf for 'authenticationEnabled=true' and look for SASL-related authentication provider configuration (saslJaasServerLoginModule)
    Affected if SASL authentication is enabled and a vulnerable Pulsar version is running
  3. Confirm SASL Role Token signer is configured
    Search Pulsar configuration files for the 'saslJaasServerRoleTokenSignerSecretPath' parameter to see if Role Token signing is active
    Affected if The SASL Role Token signer secret path is configured, enabling the timing attack surface

You are affected if you run a vulnerable Apache Pulsar version with SASL authentication and the Role Token signer feature enabled.

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.

dbcve · scoped
Upgrade available Upgrade to 2.11.3 / 3.0.2 or later
Fixed in 2.11.33.0.2
Interim mitigation

Upgrade Apache Pulsar to version 2.11.3, 3.0.2, or 3.1.1 (depending on your release line) and rotate the secret configured in saslJaasServerRoleTokenSignerSecretPath.

Recommended fix High confidence

2.11.3, 3.0.2, or 3.1.1 (depending on your current release line)

  1. 1. Identify the current Pulsar version running in your environment (Broker, Proxy, Websocket Proxy, or Function Worker).
  2. 2. Determine the appropriate upgrade target based on your current major.minor release line: for 2.11.x upgrade to 2.11.3; for 3.0.x upgrade to 3.0.2; for 3.1.x upgrade to 3.1.1; for 2.10.x or earlier, upgrade to the latest stable patched version in your preferred release line (2.11.3, 3.0.2, or 3.1.1).
  3. 3. Review the release notes for the target version to understand any configuration or behavioral changes.
  4. 4. Back up your current Pulsar configuration files, especially the `saslJaasServerRoleTokenSignerSecretPath` file contents.
  5. 5. Perform the upgrade following your organization's standard upgrade procedure (rolling upgrade or full cluster restart as appropriate for your version).
  6. 6. After upgrading, consider rotating the secret configured in `saslJaasServerRoleTokenSignerSecretPath` to a new value as an additional security measure.
  7. 7. Verify that the SASL Authentication Provider is functioning correctly after the upgrade.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Pulsar Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2023-51437 in production — separate from our analysis above.

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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
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