Process compromise via HTML push-parser context misuse
Published Jun 1, 2021 · Updated Aug 3, 2024
Use-after-free in XMLSoft libxml2 before 2.9.11 allows local users to corrupt process memory through a crafted file processed by xmllint. In the HTML push-parser path, xmllint passes an htmlParserCtxtPtr to xmlCtxtUseOptions instead of htmlCtxtUseOptions, leaving names dictionary-backed and later freed while still referenced. Exploitation requires processing the file with both --html and --push and can crash the process or enable code execution in its security context.
Summary
What happened
Use-after-free in XMLSoft libxml2 before 2.9.11 allows local users to corrupt process memory through a crafted file processed by xmllint. In the HTML push-parser path, xmllint passes an htmlParserCtxtPtr to xmlCtxtUseOptions instead of htmlCtxtUseOptions, leaving names dictionary-backed and later freed while still referenced. Exploitation requires processing the file with both --html and --push and can crash the process or enable code execution in its security context.
The record
- CVE
- CVE-2021-3516
- Published
- Jun 1, 2021
- Updated
- Aug 3, 2024
- Vendor
- XMLSoft
- Product
- libxml2
- Classifications
- T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 1, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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- Affected versionversion=libxml2 2.9.11
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What is affected?
Published CVSS scores
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Attacks
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Technologies
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Your stack
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