# CVE-2024-30255

## Summary

- **CVE ID:** CVE-2024-30255
- **Severity:** MEDIUM
- **CVSS Score:** 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
- **CWE:** CWE-390
- **Published:** Apr 4, 2024
- **Last Modified:** Mar 13, 2026

## Description

Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.

## Affected Products

- envoyproxy — envoy (>= 1.29.0, < 1.29.3)
- envoyproxy — envoy (>= 1.28.0, < 1.28.2)
- envoyproxy — envoy (>= 1.27.0, < 1.27.4)
- envoyproxy — envoy (< 1.26.8)

## References

- [CNA](https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm)
- [CNA](http://www.openwall.com/lists/oss-security/2024/04/05/3)
- [CNA](http://www.openwall.com/lists/oss-security/2024/04/03/16)
- [CVE](https://www.kb.cert.org/vuls/id/421644)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 87.81%
- **EPSS Percentile:** 99.8

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-19._