CVE-2026-26311
MEDIUM
GHSA-84xm-r438-86px
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
3Tags
Description
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.
Analysis
Envoy proxy versions before 1.37.1, 1.36.5, 1.35.8, and 1.34.13 contain a use-after-free vulnerability in the HTTP connection manager that allows attackers to trigger denial of service by sending data frames on streams after they have been reset. Public exploit code exists for this vulnerability, and no patch is currently available. …
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Remediation
Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.
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