Local compiler crash via shared classpermission reset
Published Jul 1, 2021 · Updated Nov 3, 2025
A use-after-free in the SELinux 3.2 CIL compiler allows local users to crash policy compilation via crafted CIL policy input. During AST reset, cil_reset_classperms_set recursively resets a classpermission object borrowed from the symbol table instead of clearing its non-owning pointer. Reachability requires local access to invoke the compiler on attacker-controlled policy text; the demonstrated outcome is a heap-use-after-free read and compiler crash.
Summary
What happened
A use-after-free in the SELinux 3.2 CIL compiler allows local users to crash policy compilation via crafted CIL policy input. During AST reset, cil_reset_classperms_set recursively resets a classpermission object borrowed from the symbol table instead of clearing its non-owning pointer. Reachability requires local access to invoke the compiler on attacker-controlled policy text; the demonstrated outcome is a heap-use-after-free read and compiler crash.
The record
- CVE
- CVE-2021-36086
- Published
- Jul 1, 2021
- Updated
- Nov 3, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-416
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 1, 2021CVE publishedPublication date reported by the CVE source.
- Nov 3, 2025Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Attacks
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Public exploit references
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Technologies
Your stack
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