radare2: Integer overflow causes heap out-of-bounds write in radare2 PYC parser (CVE-2026-81878) | HOL Guard CVE

Medium · CVSS 5.5CVE-2026-81878

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

Answer in brief

CVE-2026-81878 records a Medium severity (CVSS 5.5) vulnerability in radare2: Integer overflow causes heap out-of-bounds write in radare2 PYC parser. The current sources do not mark it as known exploited. The current feed maps radareorg/radare2 (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 22, 2026Updated Sep 22, 2026Source checked Sep 22, 2026First seen by HOL Sep 22, 2026Material review Sep 22, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.5
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps radareorg/radare2 (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
radareorg/radare2generic	<6.2.0	6.2.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for radareorg/radare2.
Review the reported fix. Update radareorg/radare2 to 6.2.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 22, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 22, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.