CVE-2026-27120: Leaf-kit html escaping does not work on characters that are part of extended grapheme cluster
vapor · leaf-kit
Affected: vapor leaf-kit · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 18% of scored CVEs
DescriptionCVE.org
Leafkit is a templating language with Swift-inspired syntax. Prior to 1.4.1, htmlEscaped in leaf-kit will only escape html special characters if the extended grapheme clusters match, which allows bypassing escaping by using an extended grapheme cluster containing both the special html character and some additional characters. In the case of html attributes, this can lead to XSS if there is a leaf variable in the attribute that is user controlled. This vulnerability is fixed in 1.4.1.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- vapor · leaf-kit< 1.4.1
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- vapor
- Published
- February 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-27120 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.