CVE-2026-54649

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

Published Sep 17, 2026 CVSS 4.0 · 2.1 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

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History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Punchin-app
Punchin-app punchin-email
Vendors & Products Punchin-app
Punchin-app punchin-email
Type Values Removed Values Added
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.
Title punchin-email: Operator inbox (FORWARD_TO) disclosed to correspondents on reply — Cloudflare forward() drops the relay Reply-To
Weaknesses CWE-200
CWE-201
References
Metrics cvssV4_0

{'score': 2.1, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 24, 2026, 8:55 PM
Reserved
Jun 15, 2026, 8:16 PM
Status
Deferred
Published
Sep 17, 2026, 7:16 PM
Modified
Sep 30, 2026, 5:32 PM