The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

An incorrect access control flaw was found in the kiali-operator in versions before 1.33.0 and before 1.24.7. This flaw allows an attacker with a basic level of access to the cluster (to deploy a kiali operand) to use this vulnerability and deploy a given image to anywhere in the cluster, potentially gaining access to privileged service account tokens. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

A NULL pointer dereference was found in pkg/proxy/envoy/v2/debug.go getResourceVersion in Istio pilot before 1.5.0-alpha.0. If a particular HTTP GET request is made to the pilot API endpoint, it is possible to cause the Go runtime to panic (resulting in a denial of service to the istio-pilot application).

An insufficient JWT validation vulnerability was found in Kiali versions 0.4.0 to 1.15.0 and was fixed in Kiali version 1.15.1, wherein a remote attacker could abuse this flaw by stealing a valid JWT cookie and using that to spoof a user session, possibly gaining privileges to view and alter the Istio configuration.

A hard-coded cryptographic key vulnerability in the default configuration file was found in Kiali, all versions prior to 1.15.1. A remote attacker could abuse this flaw by creating their own JWT signed tokens and bypass Kiali authentication mechanisms, possibly gaining privileges to view and alter the Istio configuration.

CNCF Envoy through 1.13.0 may consume excessive amounts of memory when responding internally to pipelined requests.

CNCF Envoy through 1.13.0 may consume excessive amounts of memory when proxying HTTP/1.1 requests or responses with many small (i.e. 1 byte) chunks.

Istio versions 1.2.10 (End of Life) and prior, 1.3 through 1.3.7, and 1.4 through 1.4.3 allows authentication bypass. The Authentication Policy exact-path matching logic can allow unauthorized access to HTTP paths even if they are configured to be only accessed after presenting a valid JWT token. For example, an attacker can add a ? or # character to a URI that would otherwise satisfy an exact-path match.

Some HTTP/2 implementations are vulnerable to a settings flood, potentially leading to a denial of service. The attacker sends a stream of SETTINGS frames to the peer. Since the RFC requires that the peer reply with one acknowledgement per SETTINGS frame, an empty SETTINGS frame is almost equivalent in behavior to a ping. Depending on how efficiently this data is queued, this can consume excess CPU, memory, or both.

Some HTTP/2 implementations are vulnerable to a header leak, potentially leading to a denial of service. The attacker sends a stream of headers with a 0-length header name and 0-length header value, optionally Huffman encoded into 1-byte or greater headers. Some implementations allocate memory for these headers and keep the allocation alive until the session dies. This can consume excess memory.