CVE-2026-81885: radare2: Infinite relocation-chain loop causes denial of service in radare2 NE parser
radare2 is a UNIX-like reverse engineering framework and command-line toolset. Prior to 6.2.0, radare2's NE relocation fixup-chain parser was vulnerable because the NE relocation parser followed fixup chains without an active iteration limit or cycle detection. The vulnerability is triggered by opening a crafted NE executable whose in-bounds relocation entry points back to itself instead of reaching 0xffff. The parser repeatedly processed the same relocation and allocated another relocation object on each iteration. This can cause denial of service through continuous CPU and memory consumption. This issue is fixed in version 6.2.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
radare2to a version that resolves this vulnerability.Fixed in 6.2.0
Event History
Frequently Asked Questions
Who is exposed to this denial-of-service condition?
Users of radare2 versions before 6.2.0 are exposed when they open or analyze a crafted NE executable. Exploitation requires the vulnerable NE relocation parser to process the malicious file.
Does exploitation require prior access or elevated privileges?
The supplied vector indicates no privileges are required, but user interaction is required. An attacker would need to persuade a user or workflow to open the crafted NE executable with radare2.
What happens when a malicious file is processed?
A self-referential, in-bounds relocation entry causes the parser to repeatedly follow the same fixup chain rather than terminating at 0xffff. Each iteration processes the relocation and allocates another relocation object, consuming CPU and memory until radare2 becomes unavailable.
What version resolves the issue?
The issue is fixed in radare2 6.2.0. Systems running versions prior to 6.2.0 should avoid processing untrusted NE executables until they can upgrade.