CVE-2026-81878
radare2: Integer overflow causes heap out-of-bounds write in radare2 PYC parser
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.
INFO
Published Date :
Sept. 22, 2026, 4:18 p.m.
Last Modified :
Sept. 25, 2026, 4:54 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update radare2 to version 6.2.0 or later.
- Avoid opening or inspecting crafted .pyc files.
- Review system security configurations.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-81878.
| URL | Resource |
|---|---|
| https://github.com/radareorg/radare2/commit/6727454b666b28c33837b219a5f91136461357c0 | Patch |
| https://github.com/radareorg/radare2/issues/26222 | Exploit Mitigation Vendor Advisory |
| https://github.com/radareorg/radare2/pull/26177 | Patch |
| https://github.com/radareorg/radare2/releases/tag/6.2.0 | Release Notes |
| https://github.com/radareorg/radare2/security/advisories/GHSA-9phv-v2w8-56j3 | Patch Vendor Advisory |
| https://github.com/radareorg/radare2/issues/26222 | Exploit Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-81878 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-81878
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-81878 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-81878 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 25, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:radare:radare2:*:*:*:*:*:*:*:* versions up to (excluding) 6.2.0 Added Reference Type GitHub, Inc.: https://github.com/radareorg/radare2/commit/6727454b666b28c33837b219a5f91136461357c0 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/radareorg/radare2/issues/26222 Types: Exploit, Mitigation, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/radareorg/radare2/pull/26177 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/radareorg/radare2/releases/tag/6.2.0 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/radareorg/radare2/security/advisories/GHSA-9phv-v2w8-56j3 Types: Patch, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/radareorg/radare2/issues/26222 Types: Exploit, Mitigation, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 22, 2026
Action Type Old Value New Value Added Reference https://github.com/radareorg/radare2/issues/26222 Added SSVC {'id': 'CVE-2026-81878', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-22T17:54:59.836434Z'} -
New CVE Received by [email protected]
Sep. 22, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Added CWE CWE-787 Added CWE CWE-190 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/81xxx/CVE-2026-81878.json">CVE-2026-81878</a> Added Reference https://github.com/radareorg/radare2/commit/6727454b666b28c33837b219a5f91136461357c0 Added Reference https://github.com/radareorg/radare2/issues/26222 Added Reference https://github.com/radareorg/radare2/pull/26177 Added Reference https://github.com/radareorg/radare2/releases/tag/6.2.0 Added Reference https://github.com/radareorg/radare2/security/advisories/GHSA-9phv-v2w8-56j3