CVE-2023-51437

Apache Pulsar: Timing attack in SASL token signature verification

HIGH
7.4
CVSS Score
Published: February 7, 2024 at 09:18 AM UTC
Updated: June 17, 2026 at 06:40 AM UTC
1 product affected across 1 vendorPulsar

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Severity
HIGH7.4
Exploit prediction
EPSS 0.8%
SSVC
No known exploit

Description

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/ .

Affected

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

v ≤ 2.10.52.11.0 ≤ v ≤ 2.11.22.11.0 ≤ v < 2.11.33.0.0 ≤ v ≤ 3.0.13.0.0 ≤ v < 3.0.22.11.03.0.03.1.03.1.0 candidate_1
Affected range stops below 2.11.3, so it looks safe — our inference, not a vendor statement
Affected range stops below 3.0.2, 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

SSVCNo known exploitNot automatablePartial impact

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

CVSS

7.4HIGHapache
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-203

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