CVE-2021-35525

Name: CVE-2021-35525
Creator: NVD / NIST
Published: 2021-06-28T18:15:08.03+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 1.62%

Last modified Jun 17, 2026

CVE-2021-35525 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. PostSRSd before 1.11 allows a denial of service (subprocess hang) if Postfix sends certain long data fields such as multiple concatenated email addresses. NOTE: the PostSRSd maintainer acknowledges "theoretically, this error should never occur ... EPSS estimates a 1.62% chance of exploitation in the next 30 days.

Description

PostSRSd before 1.11 allows a denial of service (subprocess hang) if Postfix sends certain long data fields such as multiple concatenated email addresses. NOTE: the PostSRSd maintainer acknowledges "theoretically, this error should never occur ... I'm not sure if there's a reliable way to trigger this condition by an external attacker, but it is a security bug in PostSRSd nevertheless."

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS Probability

1.62%

73.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Postsrsd Project	Postsrsd	< 1.11

References

https://bugs.gentoo.org/793674Issue Tracking, Patch, Release Notes, Third Party Advisory
https://github.com/roehling/postsrsd/commit/077be98d8c8a9847e4ae0c7dc09e7474cbe27db2Patch, Third Party Advisory
https://github.com/roehling/postsrsd/releases/tag/1.11Release Notes, Third Party Advisory
https://security.gentoo.org/glsa/202107-08Third Party Advisory
https://bugs.gentoo.org/793674Issue Tracking, Patch, Release Notes, Third Party Advisory
https://github.com/roehling/postsrsd/commit/077be98d8c8a9847e4ae0c7dc09e7474cbe27db2Patch, Third Party Advisory
https://github.com/roehling/postsrsd/releases/tag/1.11Release Notes, Third Party Advisory
https://security.gentoo.org/glsa/202107-08Third Party Advisory

Timeline

Published: Jun 28, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-35525?

How severe is CVE-2021-35525?

CVE-2021-35525 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 1.62% probability of exploitation in the next 30 days.

How do I fix CVE-2021-35525?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-35525?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST