Graylog vulnerable to insecure source port usage for DNS queries

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2023-41045: 0.36% estimated exploitation activity in the next 30 days; percentile 29.62 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Graylog utilises only one single source port for DNS queries. Details Graylog seems to bind a single socket for outgoing DNS queries. That socket is bound to a random port number which is not changed again. This goes against recommended practice since 2008, when Dan Kaminsky discovered how easy is to carry out DNS cache poisoning attacks. In order to prevent cache poisoning with spoofed DNS responses, it is necessary to maximise the uncertainty in the choice of a source port for a DNS query. PoC The attached figure shows the source ports distribution difference between Graylog configured to use a data adapter based on DNS queries and ISC Bind. The source port distribution of the DNS queries sent from Graylog to a recursive DNS name server running Bind (CLIENTQUERY) are depicted in purple, while the queries sent from the recursive DNS server to the authoritatives (RESOLVERQUERY) are plotted in green color. As it can be observed, in contrast to ISC Bind which presents a…

Published by the source

6 Jul 2023, 20:51 UTC

Last modified by the source

6 Nov 2023, 05:04 UTC

Source last checked

26 Oct 2026, 16:16 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-g96c-x7rh-99r3

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# Patch Next advisory brief: CVE-2023-41045

Advisory: Graylog vulnerable to insecure source port usage for DNS queries
IDs: CVE-2023-41045, GHSA-g96c-x7rh-99r3
Record: https://patchnext.com/advisories/cve-2023-41045 (revision 1, source checked 26 Oct 2026, 16:16 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.graylog2:graylog2-server 5.1.3, 5.0.9. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.graylog2:graylog2-server: affected >= 5.1.0, < 5.1.3; < 5.0.9; fixed in 5.1.3, 5.0.9

## Suggested inspection (read-only)
- Maven org.graylog2:graylog2-server: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.graylog2:graylog2-server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-g96c-x7rh-99r3 (GitHub-reviewed advisory GHSA-g96c-x7rh-99r3 lists affected ranges: Maven org.graylog2:graylog2-server >=5.1.0 =0 <5.0.9)

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