CVE-2026-19872

NameCVE-2026-19872
DescriptionHTML::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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1147198

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libhtml-formhandler-perl (PTS)bookworm, trixie0.40068-2vulnerable
forky, sid0.410002-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libhtml-formhandler-perlsource(unstable)0.410002-11147198

Notes

[trixie] - libhtml-formhandler-perl <no-dsa> (Minor issue)
[bookworm] - libhtml-formhandler-perl <postponed> (Minor issue)
https://lists.security.metacpan.org/cve-announce/msg/43387502/
Fixed by: https://github.com/gshank/html-formhandler/commit/2574fdb4561f5c32d44cfbfbb3188345d49eb5a2 (0.410000)

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