Host allowlist bypass via invalid URL userinfo
Published Feb 15, 2021 · Updated Sep 16, 2024
Improper URL validation in PHP 7.3.x before 7.3.26, 7.4.x before 7.4.14, and 8.0.0 allows remote attackers to bypass host checks. FILTER_VALIDATE_URL accepts a URL whose userinfo contains a backslash, while browsers interpret the same string with a different host than PHP reports. Exploitation requires consuming code to trust the validated or parsed host, enabling attacker-controlled navigation and limited data exposure.
Summary
What happened
Improper URL validation in PHP 7.3.x before 7.3.26, 7.4.x before 7.4.14, and 8.0.0 allows remote attackers to bypass host checks. FILTER_VALIDATE_URL accepts a URL whose userinfo contains a backslash, while browsers interpret the same string with a different host than PHP reports. Exploitation requires consuming code to trust the validated or parsed host, enabling attacker-controlled navigation and limited data exposure.
The record
- CVE
- CVE-2020-7071
- Published
- Feb 15, 2021
- Updated
- Sep 16, 2024
- Vendor
- The PHP Group
- Product
- PHP
- Classifications
- CWE-20, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 15, 2021CVE publishedPublication date reported by the CVE source.
- Sep 16, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=7.3.x <7.3.26
- Affected versionversion=7.4.x <7.4.14
- Affected versionversion=8.0.X <8.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Upstream invalid-userinfo reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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