Unintended file read via percent-encoded NUL truncation
Published Nov 29, 2021 · Updated Sep 17, 2024
Path truncation in PHP 7.3.x before 7.3.33, 7.4.x before 7.4.26, and 8.0.x before 8.0.13 allows attackers to read unintended files. PHP's libxml filename wrappers URL-decode percent-encoded NUL bytes, causing XML functions to discard the filename suffix after %00. Application code must pass an attacker-controlled filename to an affected XML function, and disclosure is limited to files readable by the PHP process.
Summary
What happened
Path truncation in PHP 7.3.x before 7.3.33, 7.4.x before 7.4.26, and 8.0.x before 8.0.13 allows attackers to read unintended files. PHP's libxml filename wrappers URL-decode percent-encoded NUL bytes, causing XML functions to discard the filename suffix after %00. Application code must pass an attacker-controlled filename to an affected XML function, and disclosure is limited to files readable by the PHP process.
The record
- CVE
- CVE-2021-21707
- Published
- Nov 29, 2021
- Updated
- Sep 17, 2024
- Vendor
- The PHP Group
- Product
- PHP
- Classifications
- T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 29, 2021CVE publishedPublication date reported by the CVE source.
- Sep 17, 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 <7.3.33
- Affected versionversion=7.4.x <7.4.26
- Affected versionversion=8.0.X <8.0.13
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.
Weakness, pattern, technique
Public exploit references
- PHP bug 79971 reproductionproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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