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Fencer Vulns
medium 5.3

CVE-2021-35525 json

PostSRSd before 1.11 allows a denial of service (subprocess hang) if Postfix sends certain long data fields such as multiple concatenated e…

published 2021-06-28 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-22161

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

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."

Patch / fix

  • postsrsd_project postsrsd 1.11
  • postsrsd Debian 14, Debian 13, Debian 12 1.10-2

debian advisories DEBIAN-CVE-2021-35525

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-35525 updated cvss 7.5

postsrsd: Denial of service (subprocess hang) if Postfix sends certain long data fields

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.65% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

References

Sources

Fencer Vulns 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.