What’s Vulnerable › Vulnerabilities

CVE-2026-17552: Plack::App::Prerender versions before 0.3.0 for Perl can proxy to an arbitrary host via unvalidated REQUEST_URI concatenation in call

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-27 · updated 2026-10-24
• Weakness: CWE-918

Description

Plack::App::Prerender versions before 0.3.0 for Perl can proxy to an arbitrary host via unvalidated REQUEST_URI concatenation in call. When the rewrite base is a plain string, the REQUEST_URI is appended to it, with no check that the path starts with a forward slash ('/'). When the rewrite base does not contain a path (which is the standard given in the SYNOPSIS), an attacker can create a request that changes the hostname. A request target starting with an at-sign ('@') changes the base to a RFC 3986 userinfo component. For example, a rewrite base of "https://example.com" with the submitted request "GET @192.168.1.2/" will send a request to "https://example.com@192.168.1.2/", with the rendered content returned to the attacker. This allows an attacker to access internal or restricted hosts that only the webserver has access to.

Affected products

• RRWO Plack::App::Prerender: before 0.3.0 — fixed in 0.3.0

How to fix

Upgrade to a fixed version: RRWO Plack::App::Prerender 0.3.0. Check the vendor advisory for mitigations.

References

• https://github.com/robrwo/perl-Plack-App-Prerender/commit/2d793dd69e2b6f4e469618ee742bd8402677202d.patch
• https://github.com/robrwo/perl-Plack-App-Prerender/security/advisories/GHSA-6x4w-x68j-ppqq
• https://metacpan.org/release/RRWO/Plack-App-Prerender-v0.3.0/changes
• http://www.openwall.com/lists/oss-security/2026/07/28/3

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