envoyproxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0 HttpDatagramHandler decodeData use after free

Summaryinfo

A vulnerability identified as problematic has been detected in envoyproxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0. The affected element is the function decodeData of the component HttpDatagramHandler. Performing a manipulation results in use after free. This vulnerability is cataloged as CVE-2026-73512. It is possible to initiate the attack remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in envoyproxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0. This affects the function decodeData of the component HttpDatagramHandler. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on availability. The summary by CVE is:

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 HttpDatagramHandler caches the current RequestDecoder when Capsule Protocol is enabled. Stream recreation, including an internal redirect, replaces the ActiveStream and updates EnvoyQuicServerStream but does not update the handler's cached pointer. A subsequent HTTP/3 datagram can call decodeData through the freed decoder, causing invalid virtual dispatch and a process crash. The relevant scope boundary is that hTTP/3 datagrams and Capsule Protocol must be enabled, and the request must enter a stream-recreation path such as an internal redirect. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-73512 since 08/12/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

Upgrading to version 1.36.10, 1.37.6, 1.38.4 or 1.39.1 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Firewall Software

Vendor

• envoyproxy

Name

• Envoy

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32
• 1.33
• 1.34
• 1.35
• 1.36
• 1.36.0
• 1.36.1
• 1.36.2
• 1.36.3
• 1.36.4
• 1.36.5
• 1.36.6
• 1.36.7
• 1.36.8
• 1.36.9
• 1.37
• 1.37.0
• 1.37.1
• 1.37.2
• 1.37.3
• 1.37.4
• 1.37.5
• 1.38
• 1.38.0
• 1.38.1
• 1.38.2
• 1.38.3
• 1.39.0

License

• free

Website

• Product: https://github.com/envoyproxy/envoy/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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