Reverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-75922
StatePUBLISHED
AssignerCPANSec
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-23 19:16:28 UTC
Updated2026-08-23 21:16:28 UTC
DescriptionReverse::Proxy versions before 0.04 for Perl allow HTTP request smuggling via a percent-decoded PATH_INFO written unencoded to the upstream request line. PSGI hands PATH_INFO to an application percent-decoded, so a %XX sequence in the client URL has become a raw byte by the time the proxy sees it. The proxy appends that byte string to the upstream base URL, and for an Upgrade tunnel writes it into a request line it serializes itself, re-encoding nothing in either path. The HTTP client that sends the resulting URL does not validate the target either. A path containing %0d%0a therefore arrives at the upstream as a CRLF that ends the request line, and a decoded space, '?' or '#' truncates it the same way. Everything the client writes after the CRLF is read by the upstream as a second request. On the buffered path it arrives on a keep-alive connection the proxy pools and reuses for other clients. Its method, path and headers are all chosen by the client, and the upstream attributes it to the proxy, so it reaches upstream paths that the proxy's own routing does not expose.

Risk And Classification

Problem Types: CWE-93 | CWE-444 | CWE-444 CWE-444 Inconsistent Interpretation of HTTP Requests | CWE-93 CWE-93 Improper Neutralization of CRLF Sequences

References

ReferenceSourceLinkTags
metacpan.org/release/LNATION/Reverse-Proxy-0.04/source/Proxy.xs 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
metacpan.org/release/LNATION/Reverse-Proxy-0.03/source/Proxy.xs 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
www.openwall.com/lists/oss-security/2026/08/23/2 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
metacpan.org/release/LNATION/Reverse-Proxy-0.04/changes 9b29abf9-4ab0-4765-b253-1875cd9b441e metacpan.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: Upgrade to Reverse-Proxy 0.04 or later.

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