CVE-2026-26311
Use-After-Free in Envoy HTTP FilterManager Causes Stream Corruption
Publication date: 2026-03-10
Last updated on: 2026-03-11
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| envoyproxy | envoy | to 1.34.13 (exc) |
| envoyproxy | envoy | From 1.35.0 (inc) to 1.35.8 (exc) |
| envoyproxy | envoy | From 1.36.0 (inc) to 1.36.5 (exc) |
| envoyproxy | envoy | 1.37.0 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-416 | The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in Envoy's HTTP connection manager (FilterManager) and is a logic flaw that leads to Zombie Stream Filter Execution. Specifically, it is a Use-After-Free (UAF) or state-corruption issue where filter callbacks are called on an HTTP stream that has already been logically reset and cleaned up.
The problem occurs because the ActiveStream object remains valid in memory during a deferred deletion window. If a DATA frame arrives on this stream immediately after the reset, the HTTP/2 codec calls ActiveStream::decodeData, which then calls FilterManager::decodeData. However, FilterManager::decodeData does not check if the stream has been reset (via the saw_downstream_reset_ flag) and proceeds to invoke decodeData() on filters that have already been destroyed (onDestroy() called).
This vulnerability affects Envoy versions prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13 and has been fixed in those versions.
How can this vulnerability impact me? :
This vulnerability can lead to a Use-After-Free condition or state corruption within the Envoy proxy, which may cause unexpected behavior such as crashes or denial of service (DoS).
Because the vulnerability allows execution of callbacks on already cleaned-up streams, it could potentially be exploited to disrupt the normal operation of the proxy, impacting availability.
The CVSS score of 5.9 with an impact on availability (A:H) indicates a moderate severity primarily affecting service availability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, upgrade Envoy to one of the fixed versions: 1.37.1, 1.36.5, 1.35.8, or 1.34.13.