Critical Vulnerabilities Discovered in CISA's Malcolm Tool
Executive Summary
In August 2026, multiple vulnerabilities were identified in CISA's Malcolm network traffic analysis tool, including CVE-2026-55676, CVE-2026-63133, CVE-2026-63134, CVE-2026-63177, CVE-2026-19670, and CVE-2026-19671. These flaws ranged from unbounded archive extraction leading to denial-of-service conditions to path traversal issues allowing unauthorized access. Exploitation of these vulnerabilities could enable attackers to execute arbitrary code, create unauthorized directories, or cause service disruptions. CISA promptly released patches to address these issues, urging users to update to the latest versions to mitigate potential risks. (vulners.com)
The discovery of these vulnerabilities underscores the critical importance of timely software updates and vigilant monitoring of security advisories. As cyber threats continue to evolve, organizations must prioritize the implementation of patches and adhere to best practices to safeguard their systems against potential exploits.
Why This Matters Now
The identification of these vulnerabilities in widely used network analysis tools highlights the ongoing challenges in maintaining secure software environments. Immediate attention is required to apply the provided patches, as failure to do so could leave systems susceptible to exploitation, potentially leading to data breaches or operational disruptions.
Attack Path Analysis
An attacker exploited multiple vulnerabilities in the CISA Malcolm platform, starting with an unrestricted file upload to execute arbitrary code, followed by path traversal to create directories outside intended paths, leading to unauthorized access and potential data exfiltration. The attack culminated in a denial-of-service condition by exhausting system resources through unbounded archive extraction.
Kill Chain Progression
This analysis maps confirmed threat intelligence to the full cloud kill chain to show where defensive gaps would emerge as an attack progresses.
Initial Compromise
Description
The attacker exploited an unrestricted file upload vulnerability (CVE-2026-55676) to upload and execute arbitrary PHP code on the server.
Related CVEs
CVE-2026-55676
CVSS 8.8An unrestricted file upload vulnerability in the web interface allows an authenticated remote attacker to execute arbitrary code.
Affected Products:
CISA Malcolm – <26.06.1
Exploit Status:
no public exploitCVE-2026-63133
CVSS 6.5A resource exhaustion vulnerability in the archive extraction component allows an authenticated remote attacker to cause a denial-of-service condition.
Affected Products:
CISA Malcolm – <26.07.0
Exploit Status:
no public exploitCVE-2026-63134
CVSS 5.4A path traversal vulnerability in the archive extraction component allows an authenticated remote attacker to write files outside the intended directory.
Affected Products:
CISA Malcolm – <26.07.0
Exploit Status:
no public exploitCVE-2026-63177
CVSS 7.1An authorization bypass vulnerability in the role-based access control component allows an authenticated low-privilege user to access restricted resources.
Affected Products:
CISA Malcolm – <26.07.0
Exploit Status:
no public exploitCVE-2026-19670
CVSS 5.4An authorization bypass vulnerability in the role-based access control component allows an authenticated low-privilege user to access restricted paths using percent-encoded URLs.
Affected Products:
CISA Malcolm – <=26.07.1
Exploit Status:
no public exploitCVE-2026-19671
CVSS 6.5A resource exhaustion vulnerability in the upload-processing pipeline allows an authenticated user to upload highly compressed files that decompress to an unbounded size, leading to denial-of-service.
Affected Products:
CISA Malcolm – <=26.07.1
Exploit Status:
no public exploit
MITRE ATT&CK® Techniques
Endpoint Denial of Service
Exploitation for Client Execution
Valid Accounts
Multi-Stage Channels
Application Layer Protocol
Phishing
Command and Scripting Interpreter
File and Directory Discovery
Potential Compliance Exposure
Mapping incident impact across multiple compliance frameworks.
PCI DSS 4.0 – Ensure all system components and software are protected from known vulnerabilities by installing applicable security patches
Control ID: 6.2
NYDFS 23 NYCRR 500 – Cybersecurity Policy
Control ID: 500.03
DORA – ICT Risk Management Framework
Control ID: Article 5
CISA ZTMM 2.0 – Asset Management
Control ID: 3.1
NIS2 Directive – Cybersecurity Risk Management Measures
Control ID: Article 21
Sector Implications
Industry-specific impact of the vulnerabilities, including operational, regulatory, and cloud security risks.
Government Administration
CISA Malcolm vulnerabilities enable arbitrary code execution and privilege escalation in critical network analysis infrastructure used for cybersecurity monitoring and incident response.
Law Enforcement
Network traffic analysis tool vulnerabilities compromise forensic capabilities, allowing attackers to bypass RBAC controls and execute malicious code in investigative systems.
Information Technology/IT
Multiple CVEs in Malcolm enable path traversal, file upload attacks, and DoS conditions affecting IT security operations and network monitoring infrastructures.
Computer/Network Security
Authentication bypass and code execution vulnerabilities in security analysis tools undermine threat detection capabilities and expose sensitive network intelligence data.
Sources
- CISA Malcolmhttps://www.cisa.gov/news-events/ics-advisories/icsa-26-230-01Verified
- Malcolm GitHub Security Advisorieshttps://github.com/cisagov/Malcolm/security/advisoriesVerified
- NVD CVE-2026-55676 Detailhttps://nvd.nist.gov/vuln/detail/CVE-2026-55676Verified
Frequently Asked Questions
Cloud Native Security Fabric Mitigations and ControlsCNSF
Based on the attack progression modeled above, these are the defensive controls that would constrain each stage.
Aviatrix Zero Trust CNSF is pertinent to this incident as it would likely limit the attacker's ability to move laterally and exfiltrate data by enforcing strict segmentation and identity-based access controls.
Control: Cloud Native Security Fabric (CNSF)
Mitigation: The attacker's ability to execute arbitrary code on the server would likely be constrained, reducing the potential for unauthorized actions.
Control: Zero Trust Segmentation
Mitigation: The attacker's ability to access sensitive areas would likely be limited, reducing the scope of unauthorized access.
Control: East-West Traffic Security
Mitigation: The attacker's ability to move laterally within the network would likely be constrained, reducing the potential for further compromise.
Control: Multicloud Visibility & Control
Mitigation: The attacker's ability to establish command and control channels would likely be limited, reducing the potential for remote control.
Control: Egress Security & Policy Enforcement
Mitigation: The attacker's ability to exfiltrate sensitive data would likely be constrained, reducing the potential for data loss.
The attacker's ability to cause a denial-of-service condition would likely be limited, reducing the potential for service disruption.
Impact at a Glance
Affected Business Functions
- Network Traffic Analysis
- Incident Response
- Security Monitoring
Estimated downtime: 3 days
Estimated loss: $50,000
Potential exposure of network traffic data and security logs.
Recommended Actions
Key Takeaways & Next Steps
- • Implement strict input validation and file type restrictions to prevent unauthorized file uploads.
- • Apply path traversal protections to ensure files are extracted only within intended directories.
- • Enforce robust access controls and URI normalization to prevent unauthorized access to restricted resources.
- • Monitor and limit resource consumption during file extraction processes to prevent denial-of-service conditions.
- • Regularly update and patch systems to address known vulnerabilities promptly.
