Track vulnerabilities like this one. Sign up free to get alerted when software you use is affected.

CVE-2024-27938: SMTP Smuggling in Postal

CVE-2024-27938 · published 2 years ago

Summary

What to do

Update postalserver postal to version 3.0.0 or later.

Affected software

Vendor	Product	Affected versions
postalserver	postal	< 3.0.0 `cpe:2.3:a:postalserver:postal::::::::`

Original advisory text

SMTP Smuggling in Postal

Postal is an open source SMTP server. Postal versions less than 3.0.0 are vulnerable to SMTP Smuggling attacks which may allow incoming e-mails to be spoofed. This, in conjunction with a cooperative outgoing SMTP service, would allow for an incoming e-mail to be received by Postal addressed from a server that a user has 'authorised' to send mail on their behalf but were not the genuine author of the e-mail. Postal is not affected for sending outgoing e-mails as email is re-encoded with `<CR><LF>` line endings when transmitted over SMTP. This issue has been addressed and users should upgrade to Postal v3.0.0 or higher. Once upgraded, Postal will only accept End of DATA sequences which are explicitly `<CR><LF>.<CR><LF>`. If a non-compliant sequence is detected it will be logged to the SMTP server log. There are no workarounds for this issue.

References

https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/27xxx/CVE-2024-27938... Vendor Advisory
https://nvd.nist.gov/vuln/detail/CVE-2024-27938 Vendor Advisory
https://www.postfix.org/smtp-smuggling.html URL
https://github.com/postalserver/postal/security/advisories/GHSA-j42r-6c99-hqf2 Vendor Advisory
https://github.com/postalserver/postal/commit/0140dc4 Patch
https://sec-consult.com/blog/detail/smtp-smuggling-spoofing-e-mails-worldwide Third Party Advisory

Fix within

Internet-facing 14 days

Internal 60 days

Not known to be exploited
Can be exploited automatically
Gives an attacker partial control

Severity

5.3 Medium

Exploitation

<1% chance of attack within 30 days

Type

CWE-116Improper Encoding or Escaping of Output

Timeline

Published11 Mar 2024

Updated4 Nov 2026

First seen29 Sep 2026

Sources

CVE-2024-27938 · NVD

CVE-2024-27938 · OSV

GHSA-j42r-6c99-hqf2 · GHSA

Track software like this

Free during beta