GHSA-9C3J-XM6V-J7J3
Vulnerability from github – Published: 2026-05-11 19:34 – Updated: 2026-05-11 19:34Given any pre-existing XSS / HTML injection vulnerability, an attacker can bypass the Content Security Policy's script-src directive by uploading a crafted attachment to any issue that, when accessed via the file_download.php link, will be downloaded with a valid JavaScript MIME type resulting in script execution.
The uploaded payload must be sniffed as a valid JavaScript MIME type by PHP finfo (see file_create_finfo() API function). Non-JavaScript MIME types will not get imported in a <script> tag by the browser, due to response header X-Content-Type-Options being set to nosniff, which requires all imported JavaScript files to be a valid JavaScript MIME type.
Impact
Cross-site scripting
Patches
- 9e3bee2e7b909f4e3596985892b8bc8bee9e0bfe
Workarounds
None
Credits
Thanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 2.28.1"
},
"package": {
"ecosystem": "Packagist",
"name": "mantisbt/mantisbt"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.28.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-40597"
],
"database_specific": {
"cwe_ids": [
"CWE-358",
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-11T19:34:48Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "Given any pre-existing XSS / HTML injection vulnerability, an attacker can bypass the Content Security Policy\u0027s _script-src_ directive by uploading a crafted attachment to any issue that, when accessed via the _file_download.php_ link, will be downloaded with a valid JavaScript MIME type resulting in script execution.\n\nThe uploaded payload must be sniffed as a valid JavaScript MIME type by PHP finfo (see file_create_finfo() API function). Non-JavaScript MIME types will not get imported in a `\u003cscript\u003e` tag by the browser, due to response header X-Content-Type-Options being set to _nosniff_, which requires all imported JavaScript files to be a valid JavaScript MIME type.\n\n### Impact\nCross-site scripting\n\n### Patches\n- 9e3bee2e7b909f4e3596985892b8bc8bee9e0bfe\n\n### Workarounds\nNone\n\n### Credits\nThanks to siunam (Tang Cheuk Hei) for discovering and responsibly reporting the issue.",
"id": "GHSA-9c3j-xm6v-j7j3",
"modified": "2026-05-11T19:34:48Z",
"published": "2026-05-11T19:34:48Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/mantisbt/mantisbt/security/advisories/GHSA-9c3j-xm6v-j7j3"
},
{
"type": "WEB",
"url": "https://github.com/mantisbt/mantisbt/commit/9e3bee2e7b909f4e3596985892b8bc8bee9e0bfe"
},
{
"type": "PACKAGE",
"url": "https://github.com/mantisbt/mantisbt"
},
{
"type": "WEB",
"url": "https://mantisbt.org/bugs/view.php?id=37016"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "MantisBT has a Content Security Policy bypass via attachments"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.