Is there a public exploit for CVE-2026-128069?

No public exploit for CVE-2026-128069 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-128069?

CVE-2026-128069 scores CVSS 4.7 (v3.1), rated medium.

What does CVE-2026-128069 affect?

CVE-2026-128069 affects rails-html-sanitizer.

4.7 Medium

rails-html-sanitizer: Possible XSS via shared scrubber state in concurrent calls

CVE-2026-128069

Summary Rails::HTML::SafeListSanitizer (both the HTML4 and HTML5 variants) shares one Rails::HTML::PermitScrubber across every sanitize call on the same instance, assigning its tags and attributes on each call without synchronization. Two concurrent sanitize calls with different tags: or attributes: options can interleave, so one call is scrubbed with the other call's allowlist. Versions affected: < 1.7.2 Not affected: none Fixed versions: 1.7.2 Impact Action View memoizes a single SafeListSanitizer per helper module and uses it for every sanitize call in the process, so in a multi-threaded server (for example Puma) all requests share the same PermitScrubber. If any code path calls sanitize with a more permissive allowlist, an attacker who can trigger that path concurrently with another request can cause the other request to be sanitized with the permissive allowlist. If the permissive allowlist admits script or an event-handler attribute, the strict call emits it unchanged, which is a cross-site scripting vector when the strict output is stored or rendered to other users. Applications are affected only if they run more than one thread per process and some sanitize call passes…

Assessment

CVSS: 4.7 (v3.1)
Severity: Medium
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 13 November 2026
Last updated: 13 November 2026
Affected: rails-html-sanitizer
Weakness: CWE-362, CWE-79

CVSS vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N

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