CVE-2026-32616: Pigeon has a Host Header Injection in email verification flow

Severity: high (CVSS 8.2 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: 2026-03-16 · updated 2026-06-17
Weakness: CWE-74

Description

Pigeon is a message board/notepad/social system/blog. Prior to 1.0.201, the application uses $_SERVER['HTTP_HOST'] without validation to construct email verification URLs in the register and resendmail flows. An attacker can manipulate the Host header in the HTTP request, causing the verification link sent to the user's email to point to an attacker-controlled domain. This can lead to account takeover by stealing the email verification token. This vulnerability is fixed in 1.0.201.

Affected products

kasuganosoras Pigeon: before 1.0.201

References

https://github.com/kasuganosoras/Pigeon/releases/tag/1.0.201
https://github.com/kasuganosoras/Pigeon/security/advisories/GHSA-rrj4-9wgq-prcr

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