CVE-2026-26330: envoyproxy envoy Use After Free

Vulnerability summary

CVE-2026-26330 is a high (CVSS 7.5) Use After Free vulnerability in envoyproxy envoy. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 31.6% of scored vulnerabilities.

Timeline

1. 10-03-2026
   PublishedVulnerability first disclosed.
2. 10-03-2026
   Last modifiedVulnerability information updated.

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, At the rate limit filter, if the response phase limit with apply_on_stream_done in the rate limit configuration is enabled and the response phase limit request fails directly, it may crash Envoy. When both the request phase limit and response phase limit are enabled, the safe gRPC client instance will be re-used for both the request phase request and response phase request. But after the request phase request is done, the inner state of the request phase limit request in gRPC client is not cleaned up. When a second limit request is sent at response phase, and the second limit request fails directly, the previous request's inner state may be accessed and result in crash. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.

• CWE-416Use After FreeThe 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.