What’s Vulnerable › Vulnerabilities

CVE-2026-104380: Punk versions from 0.48 before 0.55 for Perl route Extended CONNECT requests to any GET route without an Origin check in ps_serve_one

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-06 · updated 2026-10-06
• Weakness: CWE-1385

Description

Punk versions from 0.48 before 0.55 for Perl route Extended CONNECT requests to any GET route without an Origin check in ps_serve_one. On HTTP/2 and HTTP/3 a WebSocket handshake arrives as an Extended CONNECT, which is matched as a GET and so reaches every GET route, API operation and mount. The Origin check runs only when a websocket route matches. On this transport the handler's status is the handshake response, and a 2xx accepts it. A cross-origin page can open a WebSocket to any path and learn from its open or error event whether that path returns 2xx.

Affected products

• Punk: from 0.48 before 0.55 — fixed in 0.55

How to fix

Upgrade to a fixed version: Punk 0.55. Check the vendor advisory for mitigations.

References

• https://metacpan.org/release/LNATION/Punk-0.55/changes
• https://metacpan.org/release/LNATION/Punk-0.55/diff/LNATION/Punk-0.54
• http://www.openwall.com/lists/oss-security/2026/10/06/1

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