Envoy is a cloud-native, open source edge and service proxy. When an upstream TLS cluster is used with autosni enabled, a request containing a host/:authority header longer than 255 characters triggers an abnormal termination of Envoy process. Envoy does not gracefully handle an error when setting SNI for outbound TLS connection. The error can occur when Envoy attempts to use the host/:authority header value longer than 255 characters as SNI for outbound TLS connection. SNI length is limited to 255 characters per the standard. Envoy always expects this operation to succeed and abnormally aborts the process when it fails. This vulnerability is fixed in 1.30.1, 1.29.4, 1.28.3, and 1.27.5.

Envoy is a cloud-native, open source edge and service proxy. When an upstream TLS cluster is used with autosni enabled, a request containing a host/:authority header longer than 255 characters triggers an abnormal termination of Envoy process. Envoy does not gracefully handle an error when setting SNI for outbound TLS connection. The error can occur when Envoy attempts to use the host/:authority header value longer than 255 characters as SNI for outbound TLS connection. SNI length is limited to 255 characters per the standard. Envoy always expects this operation to succeed and abnormally aborts the process when it fails. This vulnerability is fixed in 1.30.1, 1.29.4, 1.28.3, and 1.27.5.

Envoy is a cloud-native, open source edge and service proxy. A crash was observed in EnvoyQuicServerStream::OnInitialHeadersComplete() with following call stack. It is a use-after-free caused by QUICHE continuing push request headers after StopReading() being called on the stream. As after StopReading(), the HCM's ActiveStream might have already be destroyed and any up calls from QUICHE could potentially cause use after free.

Envoy is a cloud-native, open source edge and service proxy. A crash was observed in EnvoyQuicServerStream::OnInitialHeadersComplete() with following call stack. It is a use-after-free caused by QUICHE continuing push request headers after StopReading() being called on the stream. As after StopReading(), the HCM's ActiveStream might have already be destroyed and any up calls from QUICHE could potentially cause use after free.

Envoy is a cloud-native, open source edge and service proxy. There is a use-after-free in HttpConnectionManager (HCM) with EnvoyQuicServerStream that can crash Envoy. An attacker can exploit this vulnerability by sending a request without FIN, then a RESETSTREAM frame, and then after receiving the response, closing the connection.

Envoy is a cloud-native, open source edge and service proxy. There is a use-after-free in HttpConnectionManager (HCM) with EnvoyQuicServerStream that can crash Envoy. An attacker can exploit this vulnerability by sending a request without FIN, then a RESETSTREAM frame, and then after receiving the response, closing the connection.

Envoy is a cloud-native, open source edge and service proxy. Due to how Envoy invoked the nlohmann JSON library, the library could throw an uncaught exception from downstream data if incomplete UTF-8 strings were serialized. The uncaught exception would cause Envoy to crash.

Envoy is a cloud-native, open source edge and service proxy. Due to how Envoy invoked the nlohmann JSON library, the library could throw an uncaught exception from downstream data if incomplete UTF-8 strings were serialized. The uncaught exception would cause Envoy to crash.

Envoy is a cloud-native, open source edge and service proxy. There is a crash at QuicheDataReader::PeekVarInt62Length(). It is caused by integer underflow in the QuicStreamSequencerBuffer::PeekRegion() implementation.

Envoy is a cloud-native, open source edge and service proxy. There is a crash at QuicheDataReader::PeekVarInt62Length(). It is caused by integer underflow in the QuicStreamSequencerBuffer::PeekRegion() implementation.

Envoy is a cloud-native, open source edge and service proxy. Envoy exposed an out-of-memory (OOM) vector from the mirror response, since async HTTP client will buffer the response with an unbounded buffer.

Envoy is a cloud-native, open source edge and service proxy. Envoy exposed an out-of-memory (OOM) vector from the mirror response, since async HTTP client will buffer the response with an unbounded buffer.

Envoy is a cloud-native, open source edge and service proxy. Prior to 1.36.1, 1.35.5, 1.34.9, and 1.33.10, large requests and responses can potentially trigger TCP connection pool crashes due to flow control management in Envoy. It will happen when the connection is closing but upstream data is still coming, resulting in a buffer watermark callback nullptr reference. The vulnerability impacts TCP proxy and HTTP 1 & 2 mixed use cases based on ALPN. This vulnerability is fixed in 1.36.1, 1.35.5, 1.34.9, and 1.33.10.

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 perconnectionbufferlimitbytes (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 perconnectionbufferlimitbytes (and for HTTP/2 the initialstreamwindowsize) or increasing perrequestbufferlimitbytes / requestbodybufferlimit can reduce the likelihood of triggering the condition but does not correct the underlying memory safety flaw.

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's extauthz filter assumes that a request contains a :path pseudoheader when applying queryparameterstoset or queryparameterstoremove from an authorization response. A path-less CONNECT request makes requestheaders->Path() return null, and Filter::onComplete dereferences that pointer while parsing the query string. An unauthenticated downstream client can crash the Envoy process when the filter and authorization response use query-parameter mutation. The relevant scope boundary is that the deployment must accept path-less CONNECT and configure extauthz query-parameter mutation. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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 HTTP RBAC accepts RFC-valid opaque header bytes but evaluates saferegex values with RE2's UTF-8 subject semantics. A downstream client can preserve a prohibited marker and add an unrelated obs-text octet, causing RE2::FullMatch to return false and a negative RBAC policy to treat the invalid subject as an ordinary no-match. A byte-oriented route matcher can still observe the marker, allowing the request to reach a route intended to be denied. The relevant scope boundary is that plain positive ALLOW regexes normally fail closed, and exact, prefix, suffix, and contains matchers are not shown to have this subject-domain failure. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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 normally matches the raw request path, while servlet backends such as Apache Tomcat strip semicolon matrix parameters from each path segment before resolving the resource. Envoy's ignorepathparametersinpathmatching option instead truncates at the first semicolon and still does not match per-segment backend behavior. A remote client can use a parameterized protected segment, or a parameter on an earlier segment, to make Envoy select an unprotected fallback while the backend resolves the protected resource. The relevant scope boundary is that the bypass requires both a path-based Envoy decision and a backend that strips semicolon parameters per segment. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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 forwards data for a configured non-WebSocket HTTP upgrade before the upstream accepts the upgrade. An unauthenticated HTTP/2 client can place a complete HTTP/1.1 request in extended CONNECT data; Envoy downgrades the request, writes the data unframed to a keep-alive HTTP/1.1 upstream, and returns the socket to the shared pool while the smuggled response remains queued. A different downstream client can then receive the attacker's response. The relevant scope boundary is that webSocket upgrades, plain CONNECT, disabled backend keep-alive, per-downstream pools, and maxrequestsperconnection set to 1 are not affected by the demonstrated path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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's HTTP external-authorization client can retain a stale request callback after a request is rejected. When RawHttpClientImpl::onSuccess later processes the authorization response, it can invoke callbacks after the callback owner has been destroyed, causing a use-after-free and process crash under production traffic. The relevant scope boundary is that the vulnerable path uses the HTTP extauthz client; the advisory does not establish the same trigger for unrelated filters. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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's ProdClusterManagerFactory::allocateConnPool dereferences transportsocketoptions while selecting an HTTP/3 connection pool without first checking whether the pointer is null. LoadBalancerContext implementations used by synthetic, mirror, health-check, and async-client calls can return no transport-socket options. With autoconfig and HTTP/3 enabled, routine traffic reaching one of those contexts can crash an Envoy worker. The relevant scope boundary is that the affected branch requires HTTP/3 in the protocol set and a context that supplies no transport-socket options. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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's Utility::copyInternetAddressAndPort and QUIC client-address paths reconstruct scoped IPv6 addresses through addressAsString and Ipv6Instance. The string includes a percent scope identifier that inetpton cannot parse, causing an exception or abort. Kernel-provided scoped IPv6 destinations in ORIGINALDST transparent-proxy deployments, and affected QUIC connection paths, can therefore terminate the process. The relevant scope boundary is that the HTTP usehttpheader override rejects scoped addresses earlier; the advisory's crash path requires a kernel-provided original destination or the affected QUIC path. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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, When ignorepathparametersinpathmatching is enabled, Envoy's router strips the semicolon suffix before matching but the RBAC urlpath matcher evaluates the raw path. A downstream request such as /admin;x can therefore miss a DENY rule for /admin while the router still selects the protected /admin backend. The inconsistent canonicalization allows an unauthenticated client to bypass path-based authorization. The relevant scope boundary is that the route option and a path-based RBAC rule must both be present, and the protected route must match after stripping. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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's optional oghttp2 upstream HTTP/2 codec accepts a response trailer HEADERS frame without ENDSTREAM. Envoy completes and deferred-deletes the ActiveRequest while oghttp2 keeps the stream open, leaving ClientStreamImpl with a dangling responsedecoder reference. A later frame on the stream can dispatch through the freed object and crash the process. The relevant scope boundary is that the default nghttp2 codec rejects the malformed trailers, and the trigger is upstream-only with oghttp2 enabled. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

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.

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's /stats?format=html admin endpoint uses StatsHtmlRender, which sanitizes string statistic values but emits statistic names without HTML encoding. A data-plane component such as grpcstats with statsforallmethods enabled can incorporate attacker-controlled path segments into cached dynamic statistic names. When an operator views the HTML stats page, the stored name can execute script with the admin interface's origin and issue privileged same-origin requests. The relevant scope boundary is that the admin interface must be browser-accessible and an enabled component must persist attacker-influenced text in statistic names. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

Summary Envoy crashes when JWT authentication is configured with the remote JWKS fetching, allowmissingorfailed is enabled, multiple JWT tokens are present in the request headers and the JWKS fetch fails.

Details This is caused by a re-entry bug in the JwksFetcherImpl. When the first token's JWKS fetch fails, onJwksError() callback triggers processing of the second token, which calls fetch() again on the same fetcher object.

The original callback's reset() then clears the second fetch's state (receiver and request) which causes a crash when the async HTTP response arrives.

PoC allowmissingorfailed or allowmissing is enabled The client send 2 Authorization headers the remote JWKS fetching failed There will be crash

Impact DoS and Crash

Mitigation Disable the allowmissingorfailed or allowmissing

A denial-of-service vulnerability was found in Envoy's HTTP/2 implementation. The attack chains two techniques: an HPACK compression bomb that exploits header compression to amplify a single byte on the wire into a full header allocation on the server (repeated thousands of times per request), and a Slowloris-style hold using a zero-byte HTTP/2 flow-control window that prevents the server from ever freeing the allocated memory.

A remote attacker can exploit this in Envoy's default HTTP/2 configuration to consume and hold large amounts of server memory (up to 32GB in approximately 20 seconds), rendering the server inaccessible.

This vulnerability exists in each server's default HTTP/2 configuration and requires no authentication to exploit.

External Reference: https://blog.calif.io/p/codex-discovered-a-hidden-http2-bomb

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.37.0 until 1.37.5 and 1.38.3, the HTTP OAuth2 filter (envoy.filters.http.oauth2) can leave an in-flight async token exchange attached to a downstream stream that has already been torn down. A late AsyncClient completion can still invoke OAuth2Filter methods that use StreamDecoderFilterCallbacks after that object’s lifetime has ended, causing undefined behavior, worker crashes (availability loss), and use-after-free / invalid-vptr failures under AddressSanitizer. This is a memory-safety / lifetime issue in the data plane, not a trivial config bug. Remote code execution is not claimed here; the primary demonstrated impact is DoS via crash and UB; any further impact would be deployment- and allocator-dependent. This vulnerability is fixed in 1.37.5 and 1.38.3.

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.35.11, 1.36.7, 1.37.3, and 1.38.1, in cases where UDP DNS filter is configured with local resolution containing a name with the length of 255 octets or remote resolution for a name of 255 octets long can complete successfully, a query with such name will result in abnormal process termination. The abnormal process termination is triggered by an invalid runtime precondition that the query name is strictly less than 255 octets, contradicting DNS specification rfc1035#section-2.3.4 that the name can be 255 or less octets. This vulnerability is fixed in 1.35.11, 1.36.7, 1.37.3, and 1.38.1.