Code execution via unchecked RLE8 delta offset
Published Aug 22, 2023 · Updated May 5, 2025
Heap buffer overflow in FreeImage 3.18.0 allows context-dependent attackers to execute code by supplying a crafted RLE8 BMP image. LoadPixelDataRLE8 accepts attacker-controlled delta values that can move beyond a scanline, then passes a negative remaining-byte count to a read targeting memory beyond the bitmap buffer. Opening or otherwise decoding the crafted file is required; the overwrite can crash the process or execute code in its context.
Summary
What happened
Heap buffer overflow in FreeImage 3.18.0 allows context-dependent attackers to execute code by supplying a crafted RLE8 BMP image. LoadPixelDataRLE8 accepts attacker-controlled delta values that can move beyond a scanline, then passes a negative remaining-byte count to a read targeting memory beyond the bitmap buffer. Opening or otherwise decoding the crafted file is required; the overwrite can crash the process or execute code in its context.
The record
- CVE
- CVE-2020-21427
- Published
- Aug 22, 2023
- Updated
- May 5, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-120, T1204.002, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 22, 2023CVE publishedPublication date reported by the CVE source.
- May 5, 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?
What conditions does exploitation require?
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.
Weakness, pattern, technique
Public exploit references
- heap_buffer_overflow_write.bmpproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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