Vulnerability · Published May 19, 2026 · Assigned by CPANSec
CVE-2026-5090Template::Plugin::HTML versions before 3.103 for Perl allows HTML and JavaScript to be injected
Medium 6.1
In plain English
A medium-severity cross-site scripting in Template-Toolkit. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Template::Plugin::HTML versions before 3.103 for Perl allows HTML and JavaScript to be injected. The html_filter function did not escape single quotes. HTML attributes inside of single quotes could be have code injected. For example, the variable "var" in <a id='ref' title='[% var | html %]'> would not be properly escaped. An attacker could insert some limited HTML and JavaScript, for example, var = " ' onclick='while (true) { alert(1) }'" Note that arbitrary HTML and JavaScript would be difficult to inject, because angle brackets, ampersands and double-quotes would still be escaped.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libtemplate-perl | no fix listed | DEBIAN-CVE-2026-5090 |
| Debian:13 | libtemplate-perl | no fix listed | DEBIAN-CVE-2026-5090 |
| Debian:14 | libtemplate-perl | 3.102-3 | DEBIAN-CVE-2026-5090 |
| Ubuntu:22.04:LTS | libtemplate-perl | 2.27-1ubuntu0.22.04.1 | USN-8377-1 |
| Ubuntu:22.04:LTS | libtemplate-perl | 2.27-1ubuntu0.22.04.1 | UBUNTU-CVE-2026-5090 |
| Ubuntu:24.04:LTS | libtemplate-perl | 2.27-1ubuntu0.24.04.1 | USN-8377-1 |
| Ubuntu:24.04:LTS | libtemplate-perl | 2.27-1ubuntu0.24.04.1 | UBUNTU-CVE-2026-5090 |
| Ubuntu:25.10 | libtemplate-perl | 2.27-1ubuntu0.25.10.1 | USN-8377-1 |
| Ubuntu:25.10 | libtemplate-perl | 2.27-1ubuntu0.25.10.1 | UBUNTU-CVE-2026-5090 |
| Ubuntu:26.04:LTS | libtemplate-perl | 3.102-1ubuntu0.1 | UBUNTU-CVE-2026-5090 |
| Ubuntu:26.04:LTS | libtemplate-perl | 3.102-1ubuntu0.1 | USN-8377-1 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Template-Toolkit | 0 – before 3.103 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N