CVE-2026-54649

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

State: Published
Severity: 2.1 Low
Published: Sep 17, 2026
Updated: Sep 24, 2026
Reserved: Jun 15, 2026

Read the record on cve.org

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.

Scores

CVSS	Score	Vector	Source
4.0	2.1 Low	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-201 Insertion of Sensitive Information Into Sent Data

Affected Products

Product	Versions
punchin-emailPunchIn-App	< 1.5.0Affected

References

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