What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-18 · updated 2026-10-12
• Weakness: CWE-400

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.

Affected products

• cometd: from 5.0.0, < 5.0.23; from 6.0.0, < 6.0.19; from 7.0.0, < 7.0.19; from 8.0.0, < 8.0.9

References

• https://github.com/cometd/cometd/discussions/2116
• 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/security/advisories/GHSA-cqgj-h8vf-4w59

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