CVE-2026-81878: radare2 Integer Overflow

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0020

Probability of exploitation

0.09%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-190 Integer Overflow

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
radare	radare2	< 6.2.0

References

Advisories & Patches

https://github.com/radareorg/radare2/commit/6727454b666b28c33837b219a5f91136461357c0 https://github.com/radareorg/radare2/issues/26222 https://github.com/radareorg/radare2/pull/26177 https://github.com/radareorg/radare2/security/advisories/GHSA-9phv-v2w8-56j3 https://github.com/radareorg/radare2/issues/26222

Exploits

https://github.com/radareorg/radare2/issues/26222 https://github.com/radareorg/radare2/issues/26222

Other References

https://github.com/radareorg/radare2/releases/tag/6.2.0

Frequently Asked Questions

What is CVE-2026-81878? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-81878? +

CVE-2026-81878 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0020, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-81878? +

CVE-2026-81878 affects products from radare, specifically: radare2. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-81878? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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