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Fencer Vulns
medium 4.3

CVE-2026-34754 json

MantisBT allows unauthorized users to upload attachments to restricted issues via REST API

published 2026-05-11 5 mo ago modified 2026-09-10 1 mo ago also GHSA-h4x5-gvx6-3rwc , EUVD-2026-31003

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 16%
public exploits
0
none known

Summary

Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.28.1 and prior allow an authenticated user to upload attachments to private Issues they are not authorized to access. This issue has been fixed in version 2.28.2.

Patch / fix

  • packagist mantisbt/mantisbt 2.28.2

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
GitHub 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
packagist mantisbt/mantisbt
<2.28.2
2.28.2

Affected products

  • mantisbt mantisbt

Classification

Weakness

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.