CVE-2023-51437
Apache Pulsar: Timing attack in SASL token signature verification
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/ .
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
7.4
Apache Pulsar: Timing attack in SASL token signature verification
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/ .
- Record
CVE-2023-51437- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-203
- Updated
- 2026-11-02
EUVDEUVD-2024-0609
7.4
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/ .
- Record
EUVD-2024-0609- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-c57v-4vg5-cm2x
7.4
Apache Pulsar SASL Authentication Provider observable timing discrepancy vulnerability
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/ .
- Record
GHSA-c57v-4vg5-cm2x- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-200, CWE-203
- Updated
- 2026-11-02
NVD
7.4
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/ .
- Record
CVE-2023-51437- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-203
- Updated
- 2026-11-02
OSV
7.4
Apache Pulsar: Timing attack in SASL token signature verification
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/ .
- Record
CVE-2023-51437- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-203
- Updated
- 2026-11-02
OSVGHSA-c57v-4vg5-cm2x
7.4
Apache Pulsar SASL Authentication Provider observable timing discrepancy vulnerability
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/ .
- Record
GHSA-c57v-4vg5-cm2x- CVSS 3.1
- 7.4 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-200, CWE-203
- Updated
- 2026-11-02
OSVOESA-2026-4329
9.9
pulsar security update
Pulsar is a distributed pub-sub messaging platform with a very flexible messaging model and an intuitive client API.
Security Fix(es):
Improper Authentication vulnerability in Apache Pulsar Proxy allows an attacker to connect to the /proxy-stats endpoint without authentication. The vulnerable endpoint exposes detailed statistics about live connections, along with the capability to modify the logging level of proxied connections without requiring proper authentication credentials.
This issue affects Apache Pulsar versions from 2.6.0 to 2.10.5, from 2.11.0 to 2.11.2, from 3.0.0 to 3.0.1, and 3.1.0.
The known risks include exposing sensitive information such as connected client IP and unauthorized logging level manipulation which could lead to a denial-of-service condition by significantly increasing the proxy's logging overhead. When deployed via the Apache Pulsar Helm chart within Kubernetes environments, the actual client IP might not be revealed through the load balancer's default behavior, which typically obscures the original source IP addresses when externalTrafficPolicy is being configured to "Cluster" by default. The /proxy-stats endpoint contains topic level statistics, however, in the default configuration, the topic level statistics aren't known to be exposed.
2.10 Pulsar Proxy users should upgrade to at least 2.10.6. 2.11 Pulsar Proxy users should upgrade to at least 2.11.3. 3.0 Pulsar Proxy users should upgrade to at least 3.0.2. 3.1 Pulsar Proxy users should upgrade to at least 3.1.1.
Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions. Additionally, it's imperative to recognize that the Apache Pulsar Proxy is not intended for direct exposure to the internet. The architectural design of Pulsar Proxy assumes that it will operate within a secured network environment, safeguarded by appropriate perimeter defenses.(CVE-2022-34321)
Improper Authentication vulnerability in Apache Pulsar WebSocket Proxy allows an attacker to connect to the /pingpong endpoint without authentication.
This issue affects Apache Pulsar WebSocket Proxy: from 2.8.0 through 2.8., from 2.9.0 through 2.9., from 2.10.0 through 2.10.4, from 2.11.0 through 2.11.1, 3.0.0.
The known risks include a denial of service due to the WebSocket Proxy accepting any connections, and excessive data transfer due to misuse of the WebSocket ping/pong feature.
2.10 Pulsar WebSocket Proxy users should upgrade to at least 2.10.5. 2.11 Pulsar WebSocket Proxy users should upgrade to at least 2.11.2. 3.0 Pulsar WebSocket Proxy users should upgrade to at least 3.0.1. 3.1 Pulsar WebSocket Proxy users are unaffected. Any users running the Pulsar WebSocket Proxy for 2.8, 2.9, and earlier should upgrade to one of the above patched versions.(CVE-2023-37544)
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/ .
(CVE-2023-51437)
Improper input validation in the Pulsar Function Worker allows a malicious authenticated user to execute arbitrary Java code on the Pulsar Function worker, outside of the…
- Record
OESA-2026-4329- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
OSVOESA-2026-4330
9.9
pulsar security update
Pulsar is a distributed pub-sub messaging platform with a very flexible messaging model and an intuitive client API.
Security Fix(es):
Improper Authentication vulnerability in Apache Pulsar Proxy allows an attacker to connect to the /proxy-stats endpoint without authentication. The vulnerable endpoint exposes detailed statistics about live connections, along with the capability to modify the logging level of proxied connections without requiring proper authentication credentials.
This issue affects Apache Pulsar versions from 2.6.0 to 2.10.5, from 2.11.0 to 2.11.2, from 3.0.0 to 3.0.1, and 3.1.0.
The known risks include exposing sensitive information such as connected client IP and unauthorized logging level manipulation which could lead to a denial-of-service condition by significantly increasing the proxy's logging overhead. When deployed via the Apache Pulsar Helm chart within Kubernetes environments, the actual client IP might not be revealed through the load balancer's default behavior, which typically obscures the original source IP addresses when externalTrafficPolicy is being configured to "Cluster" by default. The /proxy-stats endpoint contains topic level statistics, however, in the default configuration, the topic level statistics aren't known to be exposed.
2.10 Pulsar Proxy users should upgrade to at least 2.10.6. 2.11 Pulsar Proxy users should upgrade to at least 2.11.3. 3.0 Pulsar Proxy users should upgrade to at least 3.0.2. 3.1 Pulsar Proxy users should upgrade to at least 3.1.1.
Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions. Additionally, it's imperative to recognize that the Apache Pulsar Proxy is not intended for direct exposure to the internet. The architectural design of Pulsar Proxy assumes that it will operate within a secured network environment, safeguarded by appropriate perimeter defenses.(CVE-2022-34321)
Improper Authentication vulnerability in Apache Pulsar WebSocket Proxy allows an attacker to connect to the /pingpong endpoint without authentication.
This issue affects Apache Pulsar WebSocket Proxy: from 2.8.0 through 2.8., from 2.9.0 through 2.9., from 2.10.0 through 2.10.4, from 2.11.0 through 2.11.1, 3.0.0.
The known risks include a denial of service due to the WebSocket Proxy accepting any connections, and excessive data transfer due to misuse of the WebSocket ping/pong feature.
2.10 Pulsar WebSocket Proxy users should upgrade to at least 2.10.5. 2.11 Pulsar WebSocket Proxy users should upgrade to at least 2.11.2. 3.0 Pulsar WebSocket Proxy users should upgrade to at least 3.0.1. 3.1 Pulsar WebSocket Proxy users are unaffected. Any users running the Pulsar WebSocket Proxy for 2.8, 2.9, and earlier should upgrade to one of the above patched versions.(CVE-2023-37544)
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/ .
(CVE-2023-51437)
Improper input validation in the Pulsar Function Worker allows a malicious authenticated user to execute arbitrary Java code on the Pulsar Function worker, outside of the…
- Record
OESA-2026-4330- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
OSVOESA-2026-4331
9.9
pulsar security update
Pulsar is a distributed pub-sub messaging platform with a very flexible messaging model and an intuitive client API.
Security Fix(es):
Improper Authentication vulnerability in Apache Pulsar Proxy allows an attacker to connect to the /proxy-stats endpoint without authentication. The vulnerable endpoint exposes detailed statistics about live connections, along with the capability to modify the logging level of proxied connections without requiring proper authentication credentials.
This issue affects Apache Pulsar versions from 2.6.0 to 2.10.5, from 2.11.0 to 2.11.2, from 3.0.0 to 3.0.1, and 3.1.0.
The known risks include exposing sensitive information such as connected client IP and unauthorized logging level manipulation which could lead to a denial-of-service condition by significantly increasing the proxy's logging overhead. When deployed via the Apache Pulsar Helm chart within Kubernetes environments, the actual client IP might not be revealed through the load balancer's default behavior, which typically obscures the original source IP addresses when externalTrafficPolicy is being configured to "Cluster" by default. The /proxy-stats endpoint contains topic level statistics, however, in the default configuration, the topic level statistics aren't known to be exposed.
2.10 Pulsar Proxy users should upgrade to at least 2.10.6. 2.11 Pulsar Proxy users should upgrade to at least 2.11.3. 3.0 Pulsar Proxy users should upgrade to at least 3.0.2. 3.1 Pulsar Proxy users should upgrade to at least 3.1.1.
Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions. Additionally, it's imperative to recognize that the Apache Pulsar Proxy is not intended for direct exposure to the internet. The architectural design of Pulsar Proxy assumes that it will operate within a secured network environment, safeguarded by appropriate perimeter defenses.(CVE-2022-34321)
Improper Authentication vulnerability in Apache Pulsar WebSocket Proxy allows an attacker to connect to the /pingpong endpoint without authentication.
This issue affects Apache Pulsar WebSocket Proxy: from 2.8.0 through 2.8., from 2.9.0 through 2.9., from 2.10.0 through 2.10.4, from 2.11.0 through 2.11.1, 3.0.0.
The known risks include a denial of service due to the WebSocket Proxy accepting any connections, and excessive data transfer due to misuse of the WebSocket ping/pong feature.
2.10 Pulsar WebSocket Proxy users should upgrade to at least 2.10.5. 2.11 Pulsar WebSocket Proxy users should upgrade to at least 2.11.2. 3.0 Pulsar WebSocket Proxy users should upgrade to at least 3.0.1. 3.1 Pulsar WebSocket Proxy users are unaffected. Any users running the Pulsar WebSocket Proxy for 2.8, 2.9, and earlier should upgrade to one of the above patched versions.(CVE-2023-37544)
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/ .
(CVE-2023-51437)
Improper input validation in the Pulsar Function Worker allows a malicious authenticated user to execute arbitrary Java code on the Pulsar Function worker, outside of the…
- Record
OESA-2026-4331- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.apache.pulsar:pulsar-broker-auth-saslMaven |
before 2.11.3 | 2.11.3 |
org.apache.pulsar:pulsar-broker-auth-saslMaven |
3.0.0 up to 3.0.2 | 3.0.2 |
org.apache.pulsar:pulsar-broker-auth-saslMaven |
3.1.0 up to 3.1.1 | 3.1.1 |
org.apache.pulsar:pulsar-broker-auth-saslMaven |
before 2.11.3, plus listed versions 2.10.02.10.12.10.22.10.32.10.4 Show 33 moreShow less2.10.52.10.62.11.02.11.12.11.22.4.02.4.12.4.22.5.02.5.12.5.22.6.02.6.12.6.22.6.32.6.42.7.02.7.12.7.22.7.32.7.42.7.52.8.02.8.12.8.22.8.32.8.42.9.02.9.12.9.22.9.32.9.42.9.5 |
2.11.3 |
org.apache.pulsar:pulsar-broker-auth-saslMaven |
3.0.0 up to 3.0.2, plus listed versions 3.0.1 |
3.0.2 |
pulsaropenEuler:24.03-LTS-SP1 From an advisory covering 9 CVEs |
before 2.10.4-20.oe2403sp1 | 2.10.4-20.oe2403sp1 |
pulsaropenEuler:24.03-LTS-SP3 From an advisory covering 9 CVEs |
before 2.10.4-20.oe2403sp3 | 2.10.4-20.oe2403sp3 |
pulsaropenEuler:24.03-LTS-SP4 From an advisory covering 9 CVEs |
before 2.10.4-20.oe2403sp4 | 2.10.4-20.oe2403sp4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-51437 is a high vulnerability (CVSS 7.4) in Apache Pulsar, published February 7, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.76%, the 55th percentile. Fixed in org.apache.pulsar:pulsar-broker-auth-sasl 2.11.3.
References
lists.apache.org/thread/5kgmvvolf5tzp5rz9xjwfg2ncwvqqgl5
openwall.com/lists/oss-security/2024/02/07/1
nvd.nist.gov/vuln/detail/CVE-2023-51437
github.com/apache/pulsar/pull/21061
github.com/apache/pulsar/commit/6274fa01a75d74d559bb7e514c970f1fc07d15bc
github.com/apache/pulsar/commit/bc1019fa8ed37b8a4c8bb01e3662c6c015e1bc27
Show 16 moreShow less
github.com/apache/pulsar/commit/c05954e66ff33098aeb848f4bde51613ace7e47e
github.com/apache/pulsar/commit/c27beca64cc93848c40a374f19eaf4d3cc4f4f03
github.com/advisories/GHSA-c57v-4vg5-cm2x
github.com/CVEProject/cvelistV5/tree/main/cves/2023/51xxx/CVE-2023-51437.json
github.com/apache/pulsar
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4329
nvd.nist.gov/vuln/detail/CVE-2022-34321
nvd.nist.gov/vuln/detail/CVE-2023-37544
nvd.nist.gov/vuln/detail/CVE-2024-27135
nvd.nist.gov/vuln/detail/CVE-2024-27317
nvd.nist.gov/vuln/detail/CVE-2024-27894
nvd.nist.gov/vuln/detail/CVE-2024-28098
nvd.nist.gov/vuln/detail/CVE-2024-29834
nvd.nist.gov/vuln/detail/CVE-2025-30677
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4330
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-4331
Left out here: the rest of 3 source descriptions. The JSON record has them.