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CVE-2021-40347

20
FAUCET Score

CVE-2021-40347 is a medium-severity vulnerability affecting GNU Mailman Postorius before version 1.3.5. An authenticated attacker can send a crafted POST request to unsubscribe any user from a mailing list, and this action also reveals if the user was subscribed. The vulnerability has a CVSS score of 5.4, indicating low impact on confidentiality and integrity, and it does not appear to be actively exploited. There is no publicly available exploit code, nor has it garnered significant community or media attention.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.3.5CPE matchmatch criteria
cpe:2.3:a:postorius_project:postorius:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.4MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
2.5
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.18%
Probability of exploitation in next 30 days
EPSS Percentile
64.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0118 is in the 78th percentile among its peer group of 21,958 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

pippatch availablevia ghsa
Product: postoriusFixed in: 1.3.5

Vendor Advisories (1)

pipGHSA-v83x-78q3-gr2jmedium

GNU Mailman Postorius Access Control Issues

May 24, 2022

References

bugs.debian.org / cgi-bin/bugreport.cgi
Mailing ListThird Party Advisory
gitlab.com / mailman/postorius/-/commit/3d880c56b58bc26b32eac0799407d74b64b7474b
PatchThird Party Advisory
gitlab.com / mailman/postorius/-/issues/531
ExploitIssue TrackingPatchThird Party Advisory
gitlab.com / mailman/postorius/-/tags
Third Party Advisory
phabricator.wikimedia.org / T289798
ExploitPatchThird Party Advisory
debian.org / security/2021/dsa-4970
Third Party Advisory