CVE-2024-26256 – CVE-2024-26256 is a heap-based buffer overflow ... (How to Fix)

Q: What is the severity of CVE-2024-26256?

CVE-2024-26256 has a CVSS score of 7.8 (HIGH). CVE-2024-26256 is a heap-based buffer overflow vulnerability in Libarchive that allows remote attackers to execute arbitrary code by crafting malicious archive files. This affects any application or system that uses vulnerable versions of Libarchive to process untrusted archive files. The vulnerability is particularly dangerous for systems that automatically extract archives from untrusted sources.

📋 TL;DR

CVE-2024-26256 is a heap-based buffer overflow vulnerability in Libarchive that allows remote attackers to execute arbitrary code by crafting malicious archive files. This affects any application or system that uses vulnerable versions of Libarchive to process untrusted archive files. The vulnerability is particularly dangerous for systems that automatically extract archives from untrusted sources.

💻 Affected Systems

Products:

Libarchive
Applications using Libarchive (e.g., file managers, backup software, package managers)

Versions: Libarchive versions before 3.7.4

Operating Systems: Linux, Windows, macOS, BSD variants

Default Config Vulnerable: ⚠️ Yes

Notes: Any application linking against vulnerable Libarchive versions is affected when processing malicious archives. Common in package managers (pacman, dpkg), file archivers, and backup tools.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full remote code execution with the privileges of the application using Libarchive, potentially leading to complete system compromise, data theft, or ransomware deployment.

🟠

Likely Case

Application crash (denial of service) or limited code execution within the context of the vulnerable application, potentially allowing lateral movement or data exfiltration.

🟢

If Mitigated

No impact if proper input validation and sandboxing are implemented, or if archives are only processed from trusted sources.

🌐 Internet-Facing: HIGH - Any internet-facing service that processes user-uploaded archives (file upload portals, email gateways, cloud storage) is at significant risk.

🏢 Internal Only: MEDIUM - Internal systems that process archives from untrusted internal sources or external downloads remain vulnerable, though attack surface is reduced.

🎯 Exploit Status

Public PoC: ⚠️ Yes

Weaponized: LIKELY

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Proof-of-concept exploit code is publicly available in security advisories. Exploitation requires the victim to process a malicious archive file, which can be delivered via email, downloads, or uploads.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Libarchive 3.7.4 and later

Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-26256

Restart Required: Yes

Instructions:

1. Update Libarchive to version 3.7.4 or later using your system's package manager. 2. For Linux: Use 'sudo apt update && sudo apt upgrade libarchive' (Debian/Ubuntu) or 'sudo yum update libarchive' (RHEL/CentOS). 3. For Windows: Update through vendor channels or recompile applications with patched Libarchive. 4. Restart affected services or applications.

🔧 Temporary Workarounds

Disable automatic archive processing

all

Configure applications to not automatically extract archives from untrusted sources. Implement manual review for archive files.

Implement input validation

all

Use application-level validation to reject suspicious archive files before passing to Libarchive.

🧯 If You Can't Patch

Isolate systems that process archives in network segments with strict egress filtering.
Implement application sandboxing (e.g., containers, SELinux, AppArmor) to limit impact if exploitation occurs.

🔍 How to Verify

Check if Vulnerable:

Check Libarchive version with 'libarchive --version' or 'dpkg -l | grep libarchive' (Linux) or examine application dependencies.

Check Version:

libarchive --version 2>/dev/null || dpkg -l libarchive* 2>/dev/null || rpm -qa | grep libarchive 2>/dev/null

Verify Fix Applied:

Confirm Libarchive version is 3.7.4 or later using version check commands. Test with known safe archives to ensure functionality.

📡 Detection & Monitoring

Log Indicators:

Application crashes with segmentation faults when processing archives
Unexpected child processes spawned from archive-handling applications
Abnormal memory usage patterns in archive processing services

Network Indicators:

Unusual outbound connections from systems that process archives
Large archive file uploads followed by suspicious network activity

SIEM Query:

source="application.log" AND ("segmentation fault" OR "buffer overflow") AND process="*archive*"

📊 Metadata

CVE ID: CVE-2024-26256

CVSS v3 Score: 7.8 (HIGH)

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

CWE: CWE-122

Published: April 9, 2024

Last Updated: January 8, 2025

🔗 References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-26256 Third Party Advisory
http://www.openwall.com/lists/oss-security/2024/06/04/2 Mailing List
http://www.openwall.com/lists/oss-security/2024/06/05/1 Mailing List
https://github.com/LeSuisse/nixpkgs/commit/81b82a2934521dffef76f7ca305d8d4e22fe7262 Patch
https://github.com/libarchive/libarchive/commit/eb7939b24a681a04648a59cdebd386b1e9dc9237.patch Patch
https://github.com/libarchive/libarchive/releases/tag/v3.7.4 Release Notes
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EWANFZ6NEMXFCALXWI2AFKYBOLONAVFC/ Mailing List
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TWAMR5TY47UKVYMWQXB34CWSBNTRYMBV/ Mailing List
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-26256 Third Party Advisory
https://www.openwall.com/lists/oss-security/2024/06/04/2 Mailing List

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