radare2: Integer overflow causes heap out-of-bounds write in radare2 PYC parser
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-190 and the CVSS impact.
Summary
radare2 is a UNIX-like reverse engineering framework and command-line toolset. Prior to 6.2.0, radare2's CPython bytecode .pyc marshal parser was vulnerable because the CPython marshal readers accepted a 32-bit string length without rejecting values that overflow the size-plus-one allocation. The vulnerability is triggered by opening or inspecting a crafted .pyc file through r2 or rabin2. A length of 0xffffffff wrapped the allocation to zero before the common byte reader wrote attacker-controlled data and fill bytes beyond the heap allocation. This can cause heap memory corruption and denial of service; arbitrary code execution is possible but has not been demonstrated. This issue is fixed in version 6.2.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA radare2 (radareorg) Fixed in 6.2.0
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-81878
References
Patch 3
More radareorg Radare2 vulnerabilities
- TI-2023-25089 An out-of-bounds read in radare2 v.5.8.9 and before exists in the print_insn32 function… CVSS 3.1CRITICAL 9.8
- TI-2023-25088 An out-of-bounds read in radare2 v.5.8.9 and before exists in the print_insn32_fpu… CVSS 3.1CRITICAL 9.8
- TI-2021-12172 Radare2 has a division by zero vulnerability in Mach-O parser's rebase_buffer function. CVSS 3.1CRITICAL 10.0
- TI-2026-07640 radare2 6.1.5 Use-After-Free via gdbr_pids_list() CVSS 4.0HIGH 8.7
- TI-2026-07639 radare2 6.1.5 Use-After-Free via gdbr_threads_list() CVSS 4.0HIGH 8.7
- TI-2023-03993 Heap-based Buffer Overflow in radareorg/radare2 CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-81878 · CVE Program
- CVE-2026-81878 · NVD
- FIRST EPSS
- CVE-2026-81878 · Red Hat security data · CC BY 4.0
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