Application crash via malformed GIF LZW codes
Published Dec 28, 2021 · Updated Aug 4, 2024
Stack-based buffer overflow in gif2apng 1.9 allows context-dependent attackers to crash the application via a crafted GIF file. In DecodeLZW, an unchecked mincodesize expands clearcode beyond the 4,097-entry suffix array, and repeating LZW codes can drive pstr past the 4,097-byte str buffer. Opening attacker-supplied GIF input is required; the published proof of concept produces a segmentation fault, while the reporter found little control over the overwritten bytes.
Summary
What happened
Stack-based buffer overflow in gif2apng 1.9 allows context-dependent attackers to crash the application via a crafted GIF file. In DecodeLZW, an unchecked mincodesize expands clearcode beyond the 4,097-entry suffix array, and repeating LZW codes can drive pstr past the 4,097-byte str buffer. Opening attacker-supplied GIF input is required; the published proof of concept produces a segmentation fault, while the reporter found little control over the overwritten bytes.
The record
- CVE
- CVE-2021-45907
- Published
- Dec 28, 2021
- Updated
- Aug 4, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-787, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 28, 2021CVE publishedPublication date reported by the CVE source.
- Aug 4, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
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.
Public exploit references
- Malformed GIF proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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