Action View: Possible XSS vulnerability in Action View text helpers
- Exploited
- No known exploitation
- Fix
- Fixed in 8.0.5.2, 8.1.4.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 8.0.5.2, 8.1.4.1.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 30/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Action View is a framework for handling view template lookup and rendering and provides view helpers for building HTML. Prior to 8.1.4.1 and 8.0.5.2, with the HTML5 sanitizer (Rails::HTML5::Sanitizer, the default vendor on CRuby for applications using load_defaults 7.1 or later), Nokogiri before 1.19.5 serializes < and > unescaped inside attribute values. The Action View text helpers highlight and simple_format sanitize their input and then process the resulting HTML as a string: highlight splits it on tag boundaries to insert matches, and simple_format splits it into paragraphs on blank lines. An unescaped > or a blank line inside an attribute value could cause markup in that value, which the sanitizer left inert, to be emitted as live elements in the helper's html_safe output, possibly leading to XSS. Applications that use the HTML5 sanitizer and pass untrusted text to highlight, or to simple_format with html_options, are affected. This issue is fixed in versions 8.1.4.1 and 8.0.5.2.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure7/25Reachable over the network without a login · Unknown: No advisory context yet
- Reach17/20Affects Ruby on Rails (a widely deployed server, runtime, framework or database)
- Severity6.1/10CVSS 6.1
- No patch0/5No signal
What would change the score
- Would score about 85 if added to CISA KEV
- Would score about 80 if CISA's SSVC rates exploitation active
- Would score about 45 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 8.0.5.2, 8.1.4.1.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-126079 (Action View: Possible XSS vulnerability in Action View text helpers), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-126079 (entry last updated 2026-11-10): Affected: - rails rails: fixed in 8.0.5.2; from 8.1, fixed in 8.1.4.1 Fixed versions: 8.0.5.2, 8.1.4.1. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-126079 is not listed as of cve.now's last read. This KEV status is for CVE-2026-126079 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://github.com/rails/rails/security/advisories/GHSA-2p2f-4rq4-gjwc - https://github.com/rails/rails/commit/009ea68342d05d02087c04dae7faaa4e4c1def11 - https://github.com/rails/rails/releases/tag/v8.0.5.2 - https://github.com/rails/rails/releases/tag/v8.1.4.1 - http://github.com/rails/rails/commit/adc3a32d4abea77ed3aacf6f5fb71cfc005bef73 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-126079 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-126079.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- rails rails
fixed in 8.0.5.2; From 8.1 · fixed in 8.1.4.1
Evidence 7
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 4
- Repository
- Repository
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-126079
Is CVE-2026-126079 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-126079?
rails: before 8.0.5.2; from 8.1 before 8.1.4.1.Source: cve.now feed data
How do I fix CVE-2026-126079?
Upgrade to a fixed version: 8.0.5.2, 8.1.4.1.Source: cve.now feed data