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Fencer Vulns
medium 6.3

CVE-2021-34337 json

Mailman Core vulnerable to timing attacks

published 2023-04-15 3 y ago modified 2026-06-17 4 mo ago also GHSA-2jg5-xgvv-4wq7 , PYSEC-2023-22 , EUVD-2023-0129

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 22%
public exploits
0
none known

Summary

An issue was discovered in Mailman Core before 3.3.5. An attacker with access to the REST API could use timing attacks to determine the value of the configured REST API password and then make arbitrary REST API calls. The REST API is bound to localhost by default, limiting the ability for attackers to exploit this, but can optionally be made to listen on other interfaces.

Patch / fix

  • pypi mailman 3.3.5
  • gnu mailman 3.3.5
  • mailman3 Debian 14, Debian 13, Debian 12 3.3.7-1

debian advisories DEBIAN-CVE-2021-34337

  • python3-mailman openSUSE Tumbleweed 3.3.5-1.1
  • mailman3 openSUSE Tumbleweed 3.3.5-2.1

opensuse advisories openSUSE-SU-2024:11644-1openSUSE-SU-2024:11760-1

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-2021-34337 updated cvss 7.4

mailman: password checking timing attack in administrative REST API

  • Red Hat Enterprise Linux 6 mailman Red Hat Enterprise Linux 7 mailman Red Hat Enterprise Linux 8 mailman
    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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
21 mo ago

Exploit prediction

0.30% chance of exploitation in the next 30 days, higher than 22% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
GitHub 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
pypi mailman
<3.3.5
3.3.5

Classification

Weakness
  • CWE-208 Observable Timing Discrepancy

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.