CVE-2026-22780: Rizin Buffer Overflow Vulnerability

CVE-2026-22780 Overview

CVE-2026-22780 is a heap overflow vulnerability affecting Rizin, a UNIX-like reverse engineering framework and command-line toolset. Prior to version 0.8.2, a heap overflow can be exploited when a malicious Mach-O file containing bogus entries for the dyld chained segments is parsed by Rizin. This vulnerability enables attackers to potentially corrupt memory and cause application instability or unexpected behavior.

Critical Impact

Attackers can craft malicious Mach-O binaries that trigger heap overflow conditions during parsing, potentially leading to denial of service or limited integrity impact when analysts examine suspicious files.

Affected Products

• Rizin versions prior to 0.8.2
• librz/bin/format/mach0 component
• Systems using Rizin for Mach-O binary analysis

Discovery Timeline

• 2026-02-02 - CVE-2026-22780 published to NVD
• 2026-02-03 - Last updated in NVD database

Technical Details for CVE-2026-22780

Vulnerability Analysis

The vulnerability exists in Rizin's Mach-O file parser, specifically within the handling of dyld chained fixups. When processing Mach-O binaries, Rizin parses segment information including chained fixup data used by Apple's dynamic linker (dyld). The parser fails to properly validate entries within the chained segments structure before allocating and writing to heap memory.

This flaw is classified under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating the parser does not adequately constrain memory allocation or validate input bounds when processing the dyld chained segment entries. A crafted Mach-O file can specify malformed or excessive values in these structures, causing the parser to overflow heap buffers.

The vulnerability requires local access and user interaction—an analyst must open or process the malicious file using Rizin. While the attack complexity is low, the impact is limited to integrity and availability without direct confidentiality exposure.

Root Cause

The root cause lies in insufficient validation of dyld chained segment entries in the mach0_chained_fixups.c file. The vulnerable code path at line 200 of the chained fixups parser processes segment data without properly verifying that the provided offsets and counts fall within expected boundaries. This allows specially crafted entries to trigger writes beyond allocated heap buffer boundaries.

Attack Vector

The attack requires an adversary to craft a malicious Mach-O binary file with specially constructed dyld chained segment entries containing bogus values. The exploitation scenario involves:

1. Attacker creates a malformed Mach-O file with invalid chained fixup segment data
2. Victim downloads or receives the malicious binary for analysis
3. Victim opens the file using Rizin or any tool leveraging the affected librz library
4. The parser processes the dyld chained segments and triggers the heap overflow
5. Memory corruption occurs, potentially causing crashes or unexpected behavior

The attack is local in nature and requires the victim to actively engage with the malicious file, making social engineering a likely delivery mechanism. Researchers analyzing potentially malicious samples from untrusted sources are at particular risk.

Detection Methods for CVE-2026-22780

Indicators of Compromise

• Unexpected crashes or segmentation faults when Rizin processes Mach-O files
• Anomalous Mach-O files with unusually large or malformed dyld chained segment entries
• Memory corruption artifacts in Rizin process space during binary analysis
• Core dumps indicating heap corruption during Mach-O parsing operations

Detection Strategies

• Monitor for Rizin process crashes when handling Mach-O binaries from untrusted sources
• Implement file validation rules to detect Mach-O files with suspicious segment metadata
• Deploy application-level integrity monitoring to detect memory corruption events
• Use memory-safe analysis environments (sandboxed) when processing untrusted binaries

Monitoring Recommendations

• Enable crash reporting and logging for Rizin installations in analysis environments
• Monitor system logs for segmentation faults associated with Rizin or related processes
• Implement anomaly detection for files being analyzed that trigger repeated parsing failures
• Track heap allocation patterns during Mach-O file processing for unusual behavior

How to Mitigate CVE-2026-22780

Immediate Actions Required

• Upgrade Rizin to version 0.8.2 or later immediately
• Avoid processing untrusted Mach-O files with vulnerable Rizin versions
• Use sandboxed or isolated environments when analyzing binaries from unknown sources
• Review and validate any Mach-O files before analysis if upgrade is not immediately possible

Patch Information

The vulnerability is fixed in Rizin version 0.8.2. The security fix is documented in the GitHub Security Advisory GHSA-f3v7-xhmj-9cjj and implemented via commit 41ea75d5b07d9b41b27ae80675cdda65f1b1c989. The patch adds proper bounds validation for dyld chained segment entries before processing.

Users can obtain the patched version from the official Rizin v0.8.2 release. Additional context is available in GitHub Issue #5768 and Pull Request #5770.

Workarounds

• Run Rizin in a containerized or sandboxed environment when analyzing untrusted files
• Pre-screen Mach-O files using alternative tooling before detailed Rizin analysis
• Restrict access to Rizin installations to trusted analysts only
• Implement network segmentation to limit exposure of analysis systems

# Upgrade Rizin to patched version
# Using package manager (if available)
brew upgrade rizin

# Or build from source
git clone https://github.com/rizinorg/rizin.git
cd rizin
git checkout v0.8.2
meson build
ninja -C build
sudo ninja -C build install