Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-55674— Discourse: Cache poisoning/XSS via color scheme cookies

Quick assessment

Affected
discourse discourse
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Discourse是Discourse社区开源的一个集成人工智能技术的论坛社区平台。 Discourse 2026.1.6之前版本、2026.5.2之前版本、2026.6.1之前版本和2026.7.0之前版本存在跨站脚本漏洞，该漏洞源于color_scheme_id或dark_scheme_id cookie值未转义便渲染到颜色方案标签中，可能导致未经身份验证的攻击者注入任意HTML并绕过基于nonce的内容安全策略，在访问者浏览器中执行任意JavaScript。

CVSS 9.3 · Critical EPSS 0.59% · P47

Affected Version Matrix 3

VendorProduct Version RangeStatus
discourse discourse < 2026.1.6 affected
>= 2026.5.0-latest, < 2026.5.2 affected
>= 2026.6.0-latest, < 2026.6.1 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-55674

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Discourse: Cache poisoning/XSS via color scheme cookies
Source: CVE Program / CVE List V5
Vulnerability Description
Discourse is an open-source discussion platform. Prior to 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0, an unauthenticated attacker could send a single request with a crafted color_scheme_id (or dark_scheme_id) cookie to inject arbitrary HTML into a Discourse page. Because the cookie value was rendered into a color scheme tag without escaping, the attacker could break out of the attribute and inject a tag that bypassed Discourse's nonce-based Content Security Policy, resulting in arbitrary JavaScript execution in visitors' browsers. This issue is fixed in versions 2026.1.6, 2026.5.2, 2026.6.1, and 2026.7.0.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: CVE Program / CVE List V5
Vulnerability Title
Discourse 跨站脚本漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Discourse是Discourse社区开源的一个集成人工智能技术的论坛社区平台。 Discourse 2026.1.6之前版本、2026.5.2之前版本、2026.6.1之前版本和2026.7.0之前版本存在跨站脚本漏洞，该漏洞源于color_scheme_id或dark_scheme_id cookie值未转义便渲染到颜色方案标签中，可能导致未经身份验证的攻击者注入任意HTML并绕过基于nonce的内容安全策略，在访问者浏览器中执行任意JavaScript。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
discourse discourse < 2026.1.6 -

II. Public POCs for CVE-2026-55674

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-55674

请登录查看更多情报信息。

Vendor Advisories for CVE-2026-55674 (1)

Same Patch Batch · discourse · 2026-08-17 · 4 CVEs total

CVE-2026-53960 5.3 MEDIUM Discourse: Hidden first-post excerpt is emitted in Q&A schema JSON-LD
CVE-2026-59829 4.3 MEDIUM Discourse: Review queue exposes flag-related private message excerpts to category group mo
CVE-2026-55704 4.3 MEDIUM Discourse: Shared-draft titles and excerpts leak through group post serialization

IV. Related Vulnerabilities

Same product: discourse
Same vendor: discourse
Same weakness: CWE-79

V. Comments for CVE-2026-55674

No comments yet

Leave a comment