CVE-2024-30255
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.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 87.8%, higher than 100% of all known CVEs. Patch or mitigate before the next change window.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 87.81% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-390
- Affected
- envoyproxy/envoy
- Source
- security-advisories@github.com
EPSS 87.8% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.openwall.com/lists/oss-security/2024/04/03/16Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2024/04/05/3Mailing List
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmmPatch, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2024/04/03/16Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2024/04/05/3Mailing List
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmmPatch, Third Party Advisory
- https://www.kb.cert.org/vuls/id/421644
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.