HOMEVULNERABILITIESCVE-2021-35525
MEDIUM

CVE-2021-35525

NVD-CWE-noinfoPublished: June 28, 2021· Updated: Jun 17, 2026

5.3
CVSS v3.1

Official 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."

NVD Source

Technical Analysis

CVE-2021-35525 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected Vendors & Products

postsrsd_project1 product(s)
postsrsd
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://bugs.gentoo.org/793674
PATCHhttps://github.com/roehling/postsrsd/commit/077be98d8c8a9847e4ae0c7dc09e7474cbe27db2
PATCHhttps://bugs.gentoo.org/793674
PATCHhttps://github.com/roehling/postsrsd/commit/077be98d8c8a9847e4ae0c7dc09e7474cbe27db2
ADVISORYhttps://github.com/roehling/postsrsd/releases/tag/1.11
ADVISORYhttps://security.gentoo.org/glsa/202107-08
ADVISORYhttps://github.com/roehling/postsrsd/releases/tag/1.11
ADVISORYhttps://security.gentoo.org/glsa/202107-08

All References (8)

→
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

Quick Facts

CVE IDCVE-2021-35525
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessNVD-CWE-noinfo
CISA KEVNo
Affected1 vendor(s)
PublishedJun 28, 2021

Related CVEs (NVD-CWE-noinfo)

CVE-2009-2543
10.0
CVE-2013-2422
10.0
CVE-2009-2452
10.0
CVE-2026-46798
10.0
CVE-2005-2222
10.0
CVE-2008-6546
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-35525 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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