Editor crash via invalid UTF-8 regex scan
Published Sep 15, 2021 · Updated Aug 3, 2024
Heap-based buffer overflow in Vim before 8.2.3409 allows local users to crash the editor with a crafted Vim script. The find_match_text() function uses a character-derived length while advancing through invalid UTF-8, passing the terminating NUL and reading beyond the line buffer. Exploitation requires Vim to source attacker-controlled content; the published proof demonstrates an AddressSanitizer-detected overflow, not code execution.
Summary
What happened
Heap-based buffer overflow in Vim before 8.2.3409 allows local users to crash the editor with a crafted Vim script. The find_match_text() function uses a character-derived length while advancing through invalid UTF-8, passing the terminating NUL and reading beyond the line buffer. Exploitation requires Vim to source attacker-controlled content; the published proof demonstrates an AddressSanitizer-detected overflow, not code execution.
The record
- CVE
- CVE-2021-3778
- Published
- Sep 15, 2021
- Updated
- Aug 3, 2024
- Vendor
- Vim
- Product
- Vim
- Classifications
- CWE-122, CWE-787, T1204.002
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 15, 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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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <8.2.3409
What conditions does exploitation require?
What is affected?
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
- Crafted Vim script reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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