Vulnerability in yourls/yourls (CVE-2026-62858)
Summary
Vulnerability in yourls/yourls (CVE-2026-62858). Risk of unauthorized operations or information disclosure. Exploitable via GET /../../test. Mitigation: upgrade to 1.10.5 or later.
Original description
The description as published by the source.
Summary
YOURLS versions ≤1.10.4 contain an unauthenticated path traversal vulnerability that allows attackers to include and execute arbitrary PHP files on the server without any credentials.
Details
The vulnerability exists because YOURLS uses URL sanitization functions (yourls_sanitize_url(), yourls_esc_url()) to filter request paths, but these functions are designed to clean URLs, not filesystem paths. They preserve / and . characters, allowing ../ sequences to pass through unfiltered.
The unsanitized keyword is then directly concatenated into a filesystem path and passed to file_exists() and later include() operations, enabling path traversal attacks.
Data Flow:
HTTP Request URI (with ../)
↓
yourls_get_request() (no sanitization)
↓
yourls_sanitize_url() (preserves / and .)
↓
yourls_esc_url() (permits / and . via regex)
↓
Keyword extraction (preserves ../)
↓
file_exists(YOURLS_PAGEDIR . "/$keyword.php") ← Sink
↓
include(YOURLS_PAGEDIR . "/$keyword.php") ← Code Execution
Proof of Concept (POC)
In the concept validation, we assume that the attacker has uploaded a test.php file to the web root directory, but it cannot be accessed directly. (Of course, it could also be any path, such as /tmp/test.php)
Setup
Place a test file in web root:
./test.php:
<?php
phpinfo();
?>
Attack Request
GET /../../test HTTP/1.1
Host: target.com
Connection: close
Response (Apach…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
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-2026-62858 has been found in yourls/yourls.
Attackers can target a specific entry point like GET /../../test over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade yourls/yourls to 1.10.5 or later.
If unsure, ask your IT team or search "yourls/yourls CVE-2026-62858" on the vendor's site.
CVE-2026-62858 (yourls/yourls) — CWE-98 / CVSS v3 5.3
Attack vector: local / no user interaction
Attack surface: GET /../../test / test.php
Patched: 1.10.5 — 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-98) exists in yourls/yourls. Attackers reach the vulnerable code path via GET /../../test.
Check the vendor advisory for the affected versions of yourls/yourls. Attack surface: GET /../../test / test.php.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to 1.10.5.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /../../test requests with malformed payloads or SQL meta-characters. Run grep -r 'yourls/yourls' . 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 'yourls/yourls' . | 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
yourls/yourlsを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /../../test' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /../../testへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade yourls/yourls to 1.10.5ステージング環境で 1.10.5 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と、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /../../test on staging to confirm patch closes the vector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 Step 2 と同じログクエリ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 github.com
- web github.com