GHSA-74PJ-VP7J-2F6M
Vulnerability from github – Published: 2026-09-08 21:34 – Updated: 2026-09-10 18:31HTML::FormHandler versions before 0.410000 for Perl allow cross-site scripting via a submitted value rendered unescaped in an error message.
The wrappers and renderers that emit a form's errors interpolate the error string straight into HTML with no escaping. Two of the library's own messages, no_match and not_allowed, splice the submitted value into that string, and a failing type constraint puts the rejected value into the message it builds, which _apply_actions hands to add_error.
A field declared with a check regexp, a check list or a type constraint reaches those messages, with no custom validator and no non-default configuration. Errors rendered through an application's own escaping template layer rather than the library's rendering roles are not affected.
A request over the network that submits markup to such a field gets it back live inside the error span, running script in the victim's origin. Re-rendering a rejected value later gives the stored variant.
{
"affected": [],
"aliases": [
"CVE-2026-19872"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-08T20:17:29Z",
"severity": "MODERATE"
},
"details": "HTML::FormHandler versions before 0.410000 for Perl allow cross-site scripting via a submitted value rendered unescaped in an error message.\n\nThe wrappers and renderers that emit a form\u0027s errors interpolate the error string straight into HTML with no escaping. Two of the library\u0027s own messages, no_match and not_allowed, splice the submitted value into that string, and a failing type constraint puts the rejected value into the message it builds, which _apply_actions hands to add_error.\n\nA field declared with a check regexp, a check list or a type constraint reaches those messages, with no custom validator and no non-default configuration. Errors rendered through an application\u0027s own escaping template layer rather than the library\u0027s rendering roles are not affected.\n\nA request over the network that submits markup to such a field gets it back live inside the error span, running script in the victim\u0027s origin. Re-rendering a rejected value later gives the stored variant.",
"id": "GHSA-74pj-vp7j-2f6m",
"modified": "2026-09-10T18:31:33Z",
"published": "2026-09-08T21:34:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-19872"
},
{
"type": "WEB",
"url": "https://github.com/gshank/html-formhandler/commit/2574fdb4561f5c32d44cfbfbb3188345d49eb5a2.patch"
},
{
"type": "WEB",
"url": "https://metacpan.org/release/ABRAXXA/HTML-FormHandler-0.410000/changes"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2026/09/08/15"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.