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Vulnerabilities

Vulnerability · CVE-2026-75922

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.

Published Aug 23, 2026 · catalog updated Oct 14, 2026 · Reverse::Proxy versions before 0.04

Check if you run it

No confirmed exploitation is on record for CVE-2026-75922. EPSS is 0.42%. Act only if a listed version of Reverse::Proxy versions before 0.04 is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Reverse::Proxy versions before 0.04).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.42%
Remediation
Advisory link
Affected products
See sources for product scope

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. 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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-75922

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-75922. EPSS is 0.42%. Act only if a listed version of Reverse::Proxy versions before 0.04 is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-444: HTTP Request Smuggling; CWE-93. EPSS 0.42%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 23, 2026 · NIST NVD

    Detected

    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. 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

  2. Oct 14, 2026 · NIST NVD

    Updated

    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. 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

Sources

  • CVE.orgVulnerability recordCVE-2026-75922

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-75922

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-75922

    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. 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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.