Back
CVE-2026-28499
LeafKit's HTML escaping may be skipped for Collection values, enabling XSS
Medium6.9EPSS 0.28%
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
LeafKit is a templating language with Swift-inspired syntax. Prior to version 1.14.2, HTML escaping doesn't work correctly when a template prints a collection (Array / Dictionary) via `#(value)`. This can result in XSS, allowing potentially untrusted input to be rendered unescaped. Version 1.14.2 fixes the issue.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | Medium6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N |
| NVDNVD · Analyzed | 4.0 | Medium6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.28% · top 79% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.9.
Weakness
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)All about CWE-79 and its CVEs
- CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) (opens in a new tab)All about CWE-80 and its CVEs
- CWE-116: Improper Encoding or Escaping of Output (opens in a new tab)All about CWE-116 and its CVEs
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- SwiftURLgithub.com/vapor/leaf-kitGHSA-6jj5-j4j8-8473 (opens in a new tab)
References (3)
- https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/vapor/leaf-kit/commit/6044b844caa858a0c5f2505ac166f5a057c990dc (opens in a new tab)x_refsource_MISC
- https://github.com/vapor/leaf-kit/releases/tag/1.14.2 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-6jj5-j4j8-8473 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-28499)Record last updated .