Cross-Site Scripting (XSS) in lazysizes (CVE-2020-7642)
Summary
Cross-site scripting in lazysizes (CVE-2020-7642). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.2.1 or later.
Original description
The description as published by the source.
lazysizes through 5.2.0 allows execution of malicious JavaScript. The following attributes are not sanitized by the video-embed plugin: data-vimeo, data-vimeoparams, data-youtube and data-ytparams which can be abused to inject malicious JavaScript.
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-2020-7642 has been found in lazysizes.
Risk of unauthorized operations or information disclosure.
What to do: upgrade lazysizes to 5.2.1 or later.
If unsure, ask your IT team or search "lazysizes CVE-2020-7642" on the vendor's site.
CVE-2020-7642 (lazysizes) — CWE-79
Attack vector: remote (network-reachable)
Patched: 5.2.1 — 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.
Cross-site scripting (XSS) (CWE-79) exists in lazysizes.
Check the vendor advisory for the affected versions of lazysizes.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 5.2.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'lazysizes' . 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
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1Identify exposure identify
grep -r 'lazysizes' . | 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
lazysizesを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade lazysizes to 5.2.1ステージング環境で 5.2.1 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。
-
3Post-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
References
- advisory nvd.nist.gov
- patch github.com
- report snyk.io