What’s Vulnerable › Vulnerabilities

CVE-2026-54649: punchin-email: Operator inbox (FORWARD_TO) disclosed to correspondents on reply — Cloudflare forward() drops the relay Reply-To

• Severity: low (CVSS 2.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-17 · updated 2026-09-30
• Weakness: CWE-200

Description

punchin-email is a Cloudflare Email Worker that provides two-way role aliases while relaying mail to a private inbox. Prior to 1.5.0, handleInbound delivers inbound alias mail with message.forward(), which silently drops the added Reply-To header intended to route responses through the relay. When a correspondent sends mail to an alias and the operator replies, the mail client can send directly to the correspondent from the private FORWARD_TO inbox address, exposing that address. The disclosure is limited to the operator's own email address and does not expose third-party data or provide code execution or authentication bypass. This issue is fixed in version 1.5.0.

Affected products

• PunchIn-App punchin-email: before 1.5.0

References

• https://github.com/PunchIn-App/punchin-email/commit/593685ffc0b8eb3949a4838e7bfe1e97b953d084
• https://github.com/PunchIn-App/punchin-email/pull/66
• https://github.com/PunchIn-App/punchin-email/releases/tag/v1.5.0
• https://github.com/PunchIn-App/punchin-email/security/advisories/GHSA-2ph7-69xm-hmwv

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