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CVE-2020-5267

Vulnerability in actionview (CVE-2020-5267)

Summary

Vulnerability in actionview (CVE-2020-5267). Risk of unauthorized operations or information disclosure. Exploitable via escape_javascript. Mitigation: upgrade to 6.0.2.2 or later.

Original description

The description as published by the source.

There is a possible cross site scripting (XSS) vulnerability in ActionView's JavaScript literal escape helpers. Views that use the j or escape_javascript methods may be susceptible to XSS attacks.

Impact

There is a possible XSS vulnerability in the j and escape_javascript methods in ActionView. These methods are used for escaping JavaScript string literals. Impacted code will look something like this:

let a = `<%= j unknown_input %>`

or

let a = `<%= escape_javascript unknown_input %>`

Releases

The 6.0.2.2 and 5.2.4.2 releases are available at the normal locations.

Workarounds

For those that can't upgrade, the following monkey patch may be used:

ActionView::Helpers::JavaScriptHelper::JS_ESCAPE_MAP.merge!(
  {
    "`" => "\\`",
    "$" => "\\$"
  }
)

module ActionView::Helpers::JavaScriptHelper
  alias :old_ej :escape_javascript
  alias :old_j :j

  def escape_javascript(javascript)
    javascript = javascript.to_s
    if javascript.empty?
      result = ""
    else
      result = javascript.gsub(/(\\|<\/|\r\n|\342\200\250|\342\200\251|[\n\r"']|[`]|[$])/u, JS_ESCAPE_MAP)
    end
    javascript.html_safe? ? result.html_safe : result
  end

  alias :j :escape_javascript
end

Patches

To aid users who aren't able to upgrade immediately we have provided patches for
the two supported release series. They are in git-am format and consist of a
single changeset.

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2020-5267 has been found in actionview.
Attackers can target a specific entry point like escape_javascript over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade actionview to 6.0.2.2 or later.
If unsure, ask your IT team or search "actionview CVE-2020-5267" on the vendor's site.

CVE-2020-5267 (actionview) — CWE-80
Attack vector: remote (network-reachable)
Attack surface: escape_javascript
Patched: 6.0.2.2 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-80) exists in actionview. Attackers reach the vulnerable code path via escape_javascript.

📍 Affected scope

Check the vendor advisory for the affected versions of actionview. Attack surface: escape_javascript.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 6.0.2.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'actionview' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'actionview' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で actionview を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade actionview to 6.0.2.2

    ステージング環境で 6.0.2.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

RubyGems actionview
[{"type":"ECOSYSTEM","events":[{"introduced":"6.0.0"},{"fixed":"6.0.2.2"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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