Read the docs
TI-2026-21267 Aliases CVE-2026-26311GHSA-84xm-r438-86px

Envoy HTTP: filter chain execution on reset streams causing UAF crash

Priority MEDIUM 60CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-416 and the CVSS impact.

Summary

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, a logic vulnerability in Envoy's HTTP connection manager (FilterManager) that allows for Zombie Stream Filter Execution. This issue creates a "Use-After-Free" (UAF) or state-corruption window where filter callbacks are invoked on an HTTP stream that has already been logically reset and cleaned up. The vulnerability resides in source/common/http/filter_manager.cc within the FilterManager::decodeData method. The ActiveStream object remains valid in memory during the deferred deletion window. If a DATA frame arrives on this stream immediately after the reset (e.g., in the same packet processing cycle), the HTTP/2 codec invokes ActiveStream::decodeData, which cascades to FilterManager::decodeData. FilterManager::decodeData fails to check the saw_downstream_reset_ flag. It iterates over the decoder_filters_ list and invokes decodeData() on filters that have already received onDestroy(). This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00391 33rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed envoy (envoyproxy): 1.37.1, 1.36.5, 1.35.9 +1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
envoyproxyenvoy1.37.0 to before 1.37.1; 1.36.0 to before 1.36.5; 1.35.0 to before 1.35.9; before 1.34.131.37.1, 1.36.5, 1.35.9, 1.34.13Patch availableCNA
—github.com/envoyproxy/envoy (Go)——No fix listedGHSA-84xm-r438-86px
—github.com/envoyproxy/envoy (Go)1.36.0 – 1.36.4—No fix listedGHSA-84xm-r438-86px
—github.com/envoyproxy/envoy (Go)1.35.0 – 1.35.8—No fix listedGHSA-84xm-r438-86px
—github.com/envoyproxy/envoy (Go)up to 1.34.12—No fix listedGHSA-84xm-r438-86px
  • envoy Vendorenvoyproxy Affected 1.37.0 to before 1.37.1; 1.36.0 to before 1.36.5; 1.35.0 to before 1.35.9; before 1.34.13 Fixed in 1.37.1, 1.36.5, 1.35.9, 1.34.13 Patch available CNA
  • github.com/envoyproxy/envoy (Go) Vendor— Affected — Fixed in — No fix listed GHSA-84xm-r438-86px
  • github.com/envoyproxy/envoy (Go) Vendor— Affected 1.36.0 – 1.36.4 Fixed in — No fix listed GHSA-84xm-r438-86px
  • github.com/envoyproxy/envoy (Go) Vendor— Affected 1.35.0 – 1.35.8 Fixed in — No fix listed GHSA-84xm-r438-86px
  • github.com/envoyproxy/envoy (Go) Vendor— Affected up to 1.34.12 Fixed in — No fix listed GHSA-84xm-r438-86px

CPE configurations NVD · 2

CPEVersionsRoleVendor
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*before 1.34.13; 1.35.0 to before 1.35.8; 1.36.0 to before 1.36.5Vulnerableenvoyproxy
cpe:2.3:a:envoyproxy:envoy:1.37.0:*:*:*:*:*:*:*1.37.0Vulnerableenvoyproxy
  • cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* Versions before 1.34.13; 1.35.0 to before 1.35.8; 1.36.0 to before 1.36.5 Vulnerable ·envoyproxy
  • cpe:2.3:a:envoyproxy:envoy:1.37.0:*:*:*:*:*:*:* Versions 1.37.0 Vulnerable ·envoyproxy

Remediation

  • Fix · CNA envoy (envoyproxy) Fixed in 1.37.1, 1.36.5, 1.35.9, 1.34.13

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-26311
  2. 2026-10-03 Alias added: GHSA-84xm-r438-86px

References

Exploit 1

Advisory 1

Other 1

  • TI-2026-79288 Out-of-bounds write in Google Brotli decoder KEVCVSS 4.0CRITICAL 9.2
  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2024-20001 HTTP/2: CPU exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
  • TI-2024-18524 HTTP/2: memory exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
  • TI-2023-12215 Envoy client may fake the header `x-envoy-original-path` CVSS 3.1CRITICAL 9.1
  • TI-2023-18002 Envoy vulnerable to OAuth2 credentials exploit with permanent validity CVSS 3.1CRITICAL 9.8
See all 126 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences