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CVE-2026-73512

Envoyproxy Envoy use-after-free

7.5 HIGHPublic exploitEPSS 0.87%
  1. Published21 Sept 2026

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Envoyproxy Envoy≥ 1.37.0 < 1.37.6 · ≥ 1.38.0 < 1.38.4 · ≥ 1.39.0 < 1.39.1 · < 1.36.10

Remediation

Fixed in
Envoyproxy Envoy≥ 1.37.6

References

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Frequently asked

Is CVE-2026-73512 being actively exploited?

CVE-2026-73512 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.87%.

How severe is CVE-2026-73512?

CVE-2026-73512 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.87% probability of exploitation.

Which products are affected by CVE-2026-73512?

Affected products include Envoyproxy Envoy.

How do I fix CVE-2026-73512?

Upgrade affected software to a fixed version, for example Envoyproxy Envoy 1.37.6 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-73512 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.