CVE-2024-30255
HTTP/2: CPU exhaustion due to CONTINUATION frame flood
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
- envoyproxy · envoy
- CVSS v3.1 NVD
- 7.5 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS v3.1 GITHUB
- 5.3 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L - EPSS
- 87.81% chance of exploitation in the next 30 days, 100th percentile
- Published
- 2024-04-04
- Updated
- 2025-11-04
Proof-of-concept exploits (2)
- blackmagic2023/Envoy-CPU-Exhaustion-Vulnerability-PoC3★ · 2024-04-09
- lockness-Ko/CVE-2024-2731618★ · 2024-04-13
Security advisories
- http://www.openwall.com/lists/oss-security/2024/04/03/16
- envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm
- https://www.kb.cert.org/vuls/id/421644