CVE-2026-81878: radare2: Integer overflow causes heap out-of-bounds write in radare2 PYC parser

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-09-22 · updated 2026-09-25
Weakness: CWE-190

Description

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.

Affected products

radareorg/radare2: before 6.2.0 — fixed in 6.2.0

How to fix

Upgrade to a fixed version: radareorg/radare2 6.2.0. Check the vendor advisory for mitigations.

References

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