{"id":"CVE-2024-30255","aliases":["BIT-envoy-2024-30255","EUVD-2024-28182","GHSA-j654-3ccm-vfmm"],"status":"published","title":"HTTP/2: CPU exhaustion due to CONTINUATION frame flood","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.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.85015,"percentile":0.99715,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":true},"cwes":["CWE-390"],"published":"2024-04-04T19:41:02Z","modified":"2026-10-28T02:30:41Z","exploits":[{"source":"pocgithub","id":"blackmagic2023/Envoy-CPU-Exhaustion-Vulnerability-PoC","title":"blackmagic2023/Envoy-CPU-Exhaustion-Vulnerability-PoC","date":"2024-04-09","url":"https://github.com/blackmagic2023/Envoy-CPU-Exhaustion-Vulnerability-PoC"}],"fixes":[{"ecosystem":"Bitnami","package":"envoy","fixed_in":["1.26.8","1.27.4","1.28.2","1.29.3"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"envoy","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.26.8"},{"introduced":"1.27.0"},{"fixed":"1.27.4"},{"introduced":"1.28.0"},{"fixed":"1.28.2"},{"introduced":"1.29.0"},{"fixed":"1.29.3"}]}]}],"products":[{"vendor":"envoyproxy","product":"envoy"}],"references":[{"url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-j654-3ccm-vfmm","tags":["x_refsource_CONFIRM","x_transferred","Patch","Third Party Advisory","advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2024/04/05/3","tags":["x_transferred","Mailing List","discussion","web"]},{"url":"http://www.openwall.com/lists/oss-security/2024/04/03/16","tags":["x_transferred","Mailing List","Third Party Advisory","advisory","web"]},{"url":"https://www.kb.cert.org/vuls/id/421644","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-30255","tags":["web","advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/30xxx/CVE-2024-30255.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2024-30255","title":"HTTP/2: CPU exhaustion due to CONTINUATION frame flood","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.","status":"published","published":"2024-04-04T19:41:02.634Z","modified":"2025-11-04T18:30:33.889Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-390"],"updated_at":"2026-11-02T14:34:07.482552Z"}],"euvd":[{"id":"EUVD-2024-28182","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.","status":"published","published":"2024-04-04T19:41:02Z","modified":"2025-11-04T18:30:33Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T19:49:23.723839Z"}],"nvd":[{"id":"CVE-2024-30255","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.","status":"published","published":"2024-04-04T20:15:08.983Z","modified":"2026-06-17T07:26:36.947Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-390"],"updated_at":"2026-11-02T14:09:48.152273Z"}],"osv":[{"id":"CVE-2024-30255","title":"HTTP/2: CPU exhaustion due to CONTINUATION frame flood","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.","status":"published","published":"2024-04-04T19:41:02.634Z","modified":"2026-10-28T02:30:41.358926953Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-390"],"updated_at":"2026-11-02T15:44:40.06138Z"},{"id":"BIT-envoy-2024-30255","title":"HTTP/2: CPU exhaustion due to CONTINUATION frame flood","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.","status":"published","published":"2024-04-06T18:17:53.965Z","modified":"2026-09-08T08:47:27.664808618Z","updated_at":"2026-11-02T15:28:29.563843Z"}]}}