BIT-envoy-2025-62504

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    BIT-envoy-2025-62504

    Published: 21 Oct 2025Last Modified: 8 Sept 2026

    Summary: Envoy Lua filter use-after-free when oversized rewritten response body causes crash

    Details: Envoy is an open source edge and service proxy. Envoy versions earlier than 1.36.2, 1.35.6, 1.34.10, and 1.33.12 contain a use-after-free vulnerability in the Lua filter. When a Lua script executing in the response phase rewrites a response body so that its size exceeds the configured per_connection_buffer_limit_bytes (default 1MB), Envoy generates a local reply whose headers override the original response headers, leaving dangling references and causing a crash. This results in denial of service. Updating to versions 1.36.2, 1.35.6, 1.34.10, or 1.33.12 fixes the issue. Increasing per_connection_buffer_limit_bytes (and for HTTP/2 the initial_stream_window_size) or increasing per_request_buffer_limit_bytes / request_body_buffer_limit can reduce the likelihood of triggering the condition but does not correct the underlying memory safety flaw.

    References: https://github.com/envoyproxy/envoy/security/advisories/GHSA-gcxr-6vrp-wff3, https://nvd.nist.gov/vuln/detail/CVE-2025-62504

    Affected packages

    Package

    Name: envoy

    Purl: pkg:bitnami/envoy

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 0
    Fixed -1.33.12

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    BIT-envoy-2025-62504 | CVE-DB