SQL injection via unsafe old input deserialization
Published Jan 4, 2022 · Updated Apr 23, 2025
Deserialization in old() in CodeIgniter 4 before 4.1.6 allows remote attackers to inject objects through redirected form input. The helper calls unserialize() on session-backed input beginning with an array or string marker, allowing nested object graphs to invoke autoloadable classes. An application must pass attacker-controlled request data through withInput() and later call old(); the published working exploit reaches SQL injection.
Summary
What happened
Deserialization in old() in CodeIgniter 4 before 4.1.6 allows remote attackers to inject objects through redirected form input. The helper calls unserialize() on session-backed input beginning with an array or string marker, allowing nested object graphs to invoke autoloadable classes. An application must pass attacker-controlled request data through withInput() and later call old(); the published working exploit reaches SQL injection.
The record
- CVE
- CVE-2022-21647
- Published
- Jan 4, 2022
- Updated
- Apr 23, 2025
- Vendor
- CodeIgniter Foundation
- Product
- CodeIgniter 4
- Classifications
- CWE-502, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 4, 2022CVE publishedPublication date reported by the CVE source.
- Apr 23, 2025Record 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=< 4.1.6
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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