GHSA-w67g-2h6v-vjgq
Impact
During a security audit conducted with Claude Opus 4.6 and GPT-5.3-Codex, we identified three specific ways to bypass the XSS (cross-site-scripting) protection built into Phlex.
- The first bypass could happen if user-provided attributes with string keys were splatted into HTML tag, e.g.
div(**user_attributes). - The second bypass could happen if user-provided tag names were passed to the
tagmethod, e.g.tag(sometagnamefromuser). - The third bypass could happen if user’s links were passed to
hrefattributes, e.g.a(href: userprovidedlink).
All three of these patterns are meant to be safe and all have now been patched.
Patches
Phlex has patched all three issues and introduced new tests that run against Safari, Firefox and Chrome.
The patched versions are:
Phlex has also patched the main branch in GitHub.
Workarounds
If a project uses a secure CSP (content security policy) or if the application doesn’t use any of the above patterns, it is not at risk.
Package Versions Affected
Automatically patch vulnerabilities without upgrading
CVSS Version
Related Resources
References
https://github.com/yippee-fun/phlex/security/advisories/GHSA-w67g-2h6v-vjgq, https://github.com/yippee-fun/phlex/commit/1d85da417cb15eb8cb2f54a68d531c9b35d9d03a, https://github.com/yippee-fun/phlex/commit/556441d5a64ff93f749e8116a05b2d97264468ee, https://github.com/yippee-fun/phlex/commit/74e3d8610ffabc2cf5f241945e9df4b14dceb97d, https://github.com/yippee-fun/phlex/commit/9f56ad13bea9a7d6117fdfd510446c890709eeac, https://github.com/yippee-fun/phlex/commit/fe9ea708672f9fa42526d9b47e1cdc4634860ef1, https://github.com/yippee-fun/phlex
Basic Information
