CVE-2026-50572: Use-After-Free (CVSS 5.9)

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 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 ext_authz 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.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0068

Probability of exploitation

0.51%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-416 Use After Free

References

Other References

Frequently Asked Questions

What is CVE-2026-50572? +

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 ext_authz 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. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-50572? +

CVE-2026-50572 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0068, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-50572? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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