CVE-2026-34754 | MantisBT allows unauthorized users to upload attachments to restricted issues via REST API

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.

Published: 2026-05-20 Last update: 2026-05-20 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-34754 is rated Low Risk (19.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-34754

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-20 — 0.03% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34754

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]

Weakness enumeration for CVE-2026-34754

GitHub Security Advisory for CVE-2026-34754

GHSA-h4x5-gvx6-3rwc · Severity: medium · Ecosystem: composer — MantisBT has an Authorization Bypass that Allows Uploading Attachments to Private Issues via REST API

Affected software / configurations for CVE-2026-34754

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-34754

cvelogic Threat Intelligence