CVE-2026-40596
MantisBT is vulnerable to XSS and potential account takeover via user font family preference update
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.11.0 through 2.28.1 allow any authenticated user to inject arbitrary HTML by updating their account's font family. Upon exploitation, an XSS payload would be reflected on every MantisBT page. Leveraging another vulnerability (CSP bypass, see GHSA-9c3j-xm6v-j7j3), the attacker could achieve account takeover. This issue has been fixed in version 2.28.2.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
7.2
MantisBT is vulnerable to XSS and potential account takeover via user font family preference update
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.11.0 through 2.28.1 allow any authenticated user to inject arbitrary HTML by updating their account's font family. Upon exploitation, an XSS payload would be reflected on every MantisBT page. Leveraging another vulnerability (CSP bypass, see GHSA-9c3j-xm6v-j7j3), the attacker could achieve account takeover. This issue has been fixed in version 2.28.2.
- Record
CVE-2026-40596- CVSS 4.0
- 7.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:L/VA:L/SC:H/SI:H/SA:L - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-31492
7.2
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.11.0 through 2.28.1 allow any authenticated user to inject arbitrary HTML by updating their account's font family. Upon exploitation, an XSS payload would be reflected on every MantisBT page. Leveraging another vulnerability (CSP bypass, see GHSA-9c3j-xm6v-j7j3), the attacker could achieve account takeover. This issue has been fixed in version 2.28.2.
- Record
EUVD-2026-31492- CVSS 4.0
- 7.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:L/VA:L/SC:H/SI:H/SA:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-j3v9-553h-x28j
7.2
MantisBT is Vulnerable to XSS leading to account takeover via updating a user's font family preference
Any authenticated user can inject arbitrary HTML via updating their account's font family.
Impact
Cross-site scripting. The injected payload will be reflected in every MantisBT page.
Leveraging another vulnerability (CSP bypass, see GHSA-9c3j-xm6v-j7j3), the attacker could achieve account takeover.
Patches
- 9e8409cdd979eba86ef532756fc47c1d8112d22d
Workarounds
None
Credits
Thanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.
- Record
GHSA-j3v9-553h-x28j- CVSS 4.0
- 7.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:L/VA:L/SC:H/SI:H/SA:L - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
7.2
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.11.0 through 2.28.1 allow any authenticated user to inject arbitrary HTML by updating their account's font family. Upon exploitation, an XSS payload would be reflected on every MantisBT page. Leveraging another vulnerability (CSP bypass, see GHSA-9c3j-xm6v-j7j3), the attacker could achieve account takeover. This issue has been fixed in version 2.28.2.
- Record
CVE-2026-40596- CVSS 4.0
- 7.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:L/VA:L/SC:H/SI:H/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
7.2
MantisBT is vulnerable to XSS and potential account takeover via user font family preference update
Mantis Bug Tracker (MantisBT) is an open source issue tracker. Versions 2.11.0 through 2.28.1 allow any authenticated user to inject arbitrary HTML by updating their account's font family. Upon exploitation, an XSS payload would be reflected on every MantisBT page. Leveraging another vulnerability (CSP bypass, see GHSA-9c3j-xm6v-j7j3), the attacker could achieve account takeover. This issue has been fixed in version 2.28.2.
- Record
CVE-2026-40596- CVSS 4.0
- 7.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:L/VA:L/SC:H/SI:H/SA:L - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVGHSA-j3v9-553h-x28j
7.2
MantisBT is Vulnerable to XSS leading to account takeover via updating a user's font family preference
Any authenticated user can inject arbitrary HTML via updating their account's font family.
Impact
Cross-site scripting. The injected payload will be reflected in every MantisBT page.
Leveraging another vulnerability (CSP bypass, see GHSA-9c3j-xm6v-j7j3), the attacker could achieve account takeover.
Patches
- 9e8409cdd979eba86ef532756fc47c1d8112d22d
Workarounds
None
Credits
Thanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.
- Record
GHSA-j3v9-553h-x28j- CVSS 4.0
- 7.2 High
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:L/VA:L/SC:H/SI:H/SA:L - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
mantisbt/mantisbtPackagist |
2.11.0 to 2.28.1 | 2.28.2 |
mantisbt/mantisbtPackagist |
2.11.0 up to 2.28.2, plus listed versions 2.11.12.12.02.12.12.12.22.13.0 Show 45 moreShow less2.13.12.13.22.14.02.15.02.15.12.16.02.16.12.17.02.17.12.17.22.18.02.18.12.19.02.19.12.20.02.20.12.21.02.21.12.21.22.21.32.22.02.22.12.22.22.23.02.23.12.24.02.24.12.24.22.24.32.24.42.24.52.25.02.25.12.25.22.25.32.25.42.25.52.25.62.25.72.25.82.26.02.26.12.26.22.26.32.26.4 |
2.28.2 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-40596 is a high vulnerability (CVSS 7.2) in Mantisbt, published May 11, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in mantisbt/mantisbt 2.28.2.
References
github.com/mantisbt/mantisbt/security/advisories/GHSA-j3v9-553h-x28j
github.com/mantisbt/mantisbt/security/advisories/GHSA-9c3j-xm6v-j7j3
github.com/mantisbt/mantisbt/commit/9e8409cdd979eba86ef532756fc47c1d8112d22d
mantisbt.org/bugs/view.php?id=37011
mantisbt.org/bugs/view.php?id=37016
nvd.nist.gov/vuln/detail/CVE-2026-40596
github.com/advisories/GHSA-j3v9-553h-x28j
github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40596.json
github.com/mantisbt/mantisbt
Left out here: 6 versions. The JSON record has them.