Heap corruption via overflowing PYC string length
Published Sep 22, 2026 · Updated Sep 22, 2026
Heap buffer overflow in radare2 before 6.2.0 allows local users to corrupt memory by opening or inspecting a crafted .pyc file. The CPython marshal readers accept a 32-bit string length of 0xffffffff, wrap the size-plus-one allocation to zero, then write data and fill bytes beyond the heap allocation. Exploitation requires processing an attacker-supplied bytecode file through r2 or rabin2 and causes a process crash; arbitrary code execution remains undemonstrated.
Summary
What happened
Heap buffer overflow in radare2 before 6.2.0 allows local users to corrupt memory by opening or inspecting a crafted .pyc file. The CPython marshal readers accept a 32-bit string length of 0xffffffff, wrap the size-plus-one allocation to zero, then write data and fill bytes beyond the heap allocation. Exploitation requires processing an attacker-supplied bytecode file through r2 or rabin2 and causes a process crash; arbitrary code execution remains undemonstrated.
The record
- CVE
- CVE-2026-81878
- Published
- Sep 22, 2026
- Updated
- Sep 22, 2026
- Vendor
- radareorg
- Product
- radare2
- Classifications
- T1204.002
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 22, 2026CVE publishedPublication date reported by the CVE source.
- Sep 22, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 6.2.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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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.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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