CVE-2024-30255

5.3 MEDIUM 85% exploit odds Fix listed Denial of service Browser & mail

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 85.0% chance of exploitation in the next 30 days (EPSS). Higher than most.
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2024-04-04 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 07:26 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 85.0% in the next 30 days (EPSS).
Severity: 5.3 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2024-04-04 20:15 UTC
Last modified: 2026-06-17 07:26 UTC
Exploit probability: 85.0% · EPSS, next 30 days
Weakness: CWE-390
Record status: Modified

Affected

Envoyproxy Envoy < 1.26.8
Envoyproxy Envoy < 1.27.4
Envoyproxy Envoy < 1.28.2
Envoyproxy Envoy < 1.29.3

Attack profile CVSS 3.1 · 5.3

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2024-30255.md and follow it. Check whether this project is affected by CVE-2024-30255. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record