CVE-2026-73550
Envoy: HTTP/2 Discarded Host Header 200 GB Header-Copy OOM in Envoy
At a glance
- Source
- NVD
- EPSS
- EPSS 0.55 % · percentile 46 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
Description
Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy copies every decoded HTTP/2 Host header value before discarding it when :authority is already present. The discarded value bypasses saveHeader, so its bytes and count are not charged against request header limits. An unauthenticated client can use HPACK indexing to submit many references to a large Host value across a bounded number of streams, forcing extreme header-copy allocation and causing the proxy to be out-of-memory killed. The relevant scope boundary is that the demonstrated amplification uses HTTP/2 HPACK and the duplicate Host discard behavior. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.
Weaknesses (CWE)
- CWE-401 — Missing Release of Memory after Effective Lifetime
References
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-qgf6-qvhw-4hvh
- https://github.com/envoyproxy/envoy/commit/0910997f70e91d2d20c329bb507bfce44ce01f80
- https://github.com/envoyproxy/envoy/commit/1fec994c868df008cdd4ae285aab58a196fd31f2
- https://github.com/envoyproxy/envoy/commit/3fd0ffee7ac87adf3bc6e421656bb96310512300
- https://github.com/envoyproxy/envoy/commit/fc75d8e35b0d11acbae18b63a0bd96e32e84f61b
- https://github.com/envoyproxy/envoy/releases/tag/v1.36.10
- https://github.com/envoyproxy/envoy/releases/tag/v1.37.6
- https://github.com/envoyproxy/envoy/releases/tag/v1.38.4
- https://github.com/envoyproxy/envoy/releases/tag/v1.39.1
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · security-advisories@github.com (Secondary) |
European references
- ENISA EUVD · EUVD-2026-84111
- GCVE · GCVE-0-2026-73550
Affected configurations (NVD CPE)
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*< 1.36.10cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*≥ 1.37.0 < 1.37.6cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*≥ 1.38.0 < 1.38.4cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*≥ 1.39.0 < 1.39.1
Affected products
| Product | Versions |
|---|---|
| envoyproxy · envoy | affected < 1.36.10 ; affected >= 1.37.0, < 1.37.6 ; affected >= 1.38.0, < 1.38.4 ; affected >= 1.39.0, < 1.39.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |