Vulnerability in urijs (CVE-2020-26291)
Summary
Vulnerability in urijs (CVE-2020-26291). Data can be tampered with by attackers. Mitigation: upgrade to 1.19.4 or later.
Original description
The description as published by the source.
Impact
If using affected versions to determine a URL's hostname, the hostname can be spoofed by using a backslash (\) character followed by an at (@) character. If the hostname is used in security decisions, the decision may be incorrect.
Depending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior.
Example URL: https://expected-example.com\@observed-example.com
Escaped string: https://expected-example.com\\@observed-example.com (JavaScript strings must escape backslash)
Affected versions incorrectly return observed-example.com. Patched versions correctly return expected-example.com. Patched versions match the behavior of other parsers which implement the WHATWG URL specification, including web browsers and Node's built-in URL class.
Patches
Version 1.19.4 is patched against all known payload variants. Version 1.19.3 has a partial patch but is still vulnerable to a payload variant.
References
https://github.com/medialize/URI.js/releases/tag/v1.19.4 (complete fix for this bypass)
https://github.com/medialize/URI.js/releases/tag/v1.19.3 (partial fix for this bypass)
PR #233 (initial fix for backslash handling)
For more information
If you have any questions or comments about this advisory, open an issue in https://github.com/medialize/URI.js…
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-2020-26291 has been found in urijs.
Data can be tampered with by attackers.
What to do: upgrade urijs to 1.19.4 or later.
If unsure, ask your IT team or search "urijs CVE-2020-26291" on the vendor's site.
CVE-2020-26291 (urijs) — CWE-20
Attack vector: remote (network-reachable) / no user interaction
Patched: 1.19.4 — 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.
A vulnerability (CWE-20) exists in urijs.
Check the vendor advisory for the affected versions of urijs.
Severity: ?. Data can be tampered with by attackers.
Update to 1.19.4.
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 'urijs' . 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
-
1Identify exposure identify
grep -r 'urijs' . | 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
urijs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 urijs to 1.19.4ステージング環境で 1.19.4 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
- package github.com
- web github.com
- web github.com
- web github.com
- web npmjs.com
- web npmjs.com