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Fencer Intel
low 2.1

CVE-2026-54649 json

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

published 5mo ago modified last mo. also EUVD-2026-82386 , GHSA-2ph7-69xm-hmwv

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository PunchIn-App/punchin-email. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
2.1
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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.

Patch / fix

Is CVE-2026-54649 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.84% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 4.0 2.1 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
CNA 4.0 2.1 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • PunchIn-App punchin-email

Classification

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

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of PunchIn-App/punchin-email published their own advisory on GitHub. Reviewed sources take precedence over it.