CVE-2026-34754Network attack vector

Unauthorized attachment upload via project-level permission check

Published May 19, 2026 · Updated May 19, 2026

Improper access control in MantisBT 2.28.1 and earlier allows remote authenticated users to upload files to private issues via REST. In core/file_api.php, file_allow_bug_upload() checks the project-level upload threshold for existing issues instead of verifying issue-level access. Any authenticated account meeting the project's upload threshold can add content to an otherwise inaccessible private issue, affecting issue integrity without disclosing its contents.

CVSS severity4.3
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in MantisBT 2.28.1 and earlier allows remote authenticated users to upload files to private issues via REST. In core/file_api.php, file_allow_bug_upload() checks the project-level upload threshold for existing issues instead of verifying issue-level access. Any authenticated account meeting the project's upload threshold can add content to an otherwise inaccessible private issue, affecting issue integrity without disclosing its contents.

The record

CVE
CVE-2026-34754
Published
May 19, 2026
Updated
May 19, 2026
Vendor
MantisBT
Product
MantisBT
Classifications
CWE-284, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 19, 2026CVE publishedPublication date reported by the CVE source.
  2. May 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.28.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MantisBT · MantisBTversion=< 2.28.2

Published CVSS scores

4.3GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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