HTTP Request Smuggling The advisory has been revoked - it doesn't affect any version of package istio-proxy (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL10-ISTIOPROXY-20888474
- published14 Oct 2026
- disclosed20 Aug 2026
Introduced: 20 Aug 2026
CVE-2026-63385 (opens in a new tab)Amendment
The Red Hat security team deemed this advisory irrelevant for RHEL:10.
NVD Description
Note: Versions mentioned in the description apply only to the upstream istio-proxy package and not the istio-proxy package as distributed by RHEL.
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=2520666
- https://access.redhat.com/security/cve/CVE-2026-63385
- https://access.redhat.com/errata/RHSA-2026:63388
- https://access.redhat.com/errata/RHSA-2026:67909
- https://github.com/libevent/libevent/commit/758be0c0f69c1934ef9a84ab39e9f9e5fde2e6d0
- https://github.com/libevent/libevent/commit/9170dd35e64714613e8d13b290587cfc28e258e2
- https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable
- https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha
- https://github.com/libevent/libevent/security/advisories/GHSA-jcwh-pvf2-73p2