CVE-2026-28499
LeafKit's HTML escaping may be skipped for Collection values, enabling XSS
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.
INFO
Published Date :
March 18, 2026, 2:16 a.m.
Last Modified :
March 18, 2026, 7:48 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update LeafKit to version 1.14.2.
- Ensure collections are properly escaped when printed.
Public PoC/Exploit Available at Github
CVE-2026-28499 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-28499.
| URL | Resource |
|---|---|
| https://github.com/vapor/leaf-kit/commit/6044b844caa858a0c5f2505ac166f5a057c990dc | Patch |
| https://github.com/vapor/leaf-kit/releases/tag/1.14.2 | Release Notes |
| https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473 | Exploit Vendor Advisory |
| https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473 | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-28499 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-28499
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-28499 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-28499 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Added CPE Configuration OR *cpe:2.3:a:vapor:leafkit:*:*:*:*:*:*:*:* versions up to (excluding) 1.14.2 Added Reference Type GitHub, Inc.: https://github.com/vapor/leaf-kit/commit/6044b844caa858a0c5f2505ac166f5a057c990dc Types: Patch Added Reference Type GitHub, Inc.: https://github.com/vapor/leaf-kit/releases/tag/1.14.2 Types: Release Notes Added Reference Type CISA-ADP: https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473 Types: Exploit, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473 Types: Exploit, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mar. 18, 2026
Action Type Old Value New Value Added Reference https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473 -
New CVE Received by [email protected]
Mar. 18, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 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 Added CWE CWE-79 Added CWE CWE-116 Added CWE CWE-80 Added Reference https://github.com/vapor/leaf-kit/commit/6044b844caa858a0c5f2505ac166f5a057c990dc Added Reference https://github.com/vapor/leaf-kit/releases/tag/1.14.2 Added Reference https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473