Critical GitLab SSRF Vulnerability Under Active Exploitation, CISA Warns
The Cybersecurity and Infrastructure Security Agency (CISA) has added CVE-2021-39935, a severe server-side request forgery (SSRF) vulnerability in GitLab Community and Enterprise Editions, to its Known Exploited Vulnerabilities (KEV) catalog after confirming active exploitation in the wild.
The flaw resides in GitLab’s CI Lint API, allowing unauthenticated attackers to manipulate the server into making unauthorized requests to internal systems. By exploiting this weakness, threat actors can bypass perimeter defenses, access restricted resources, and potentially move laterally within compromised networks. The vulnerability (tracked as CWE-918) poses risks including data exposure, supply chain compromise via CI/CD pipeline manipulation, and unauthorized access to cloud metadata or internal infrastructure.
Both GitLab Community and Enterprise Editions are affected, with CISA’s inclusion in the KEV catalog underscoring the urgency of remediation. While no direct links to ransomware campaigns have been confirmed, the flaw’s potential for initial access makes it a prime target for advanced persistent threat (APT) groups and initial access brokers.
Under Binding Operational Directive 22-01, Federal Civilian Executive Branch (FCEB) agencies must patch or mitigate the vulnerability by February 24, 2026. Organizations unable to apply fixes are advised to discontinue use of affected GitLab instances until updates are available. GitLab has released patches, and administrators are urged to upgrade immediately, review CI Lint API configurations, and monitor logs for suspicious activity such as unusual API requests or unexpected internal connections originating from GitLab servers.
Cloud-hosted GitLab users should adhere to BOD 22-01 guidance for securing cloud services. The incident highlights the growing threat of SSRF attacks, which can evade traditional security measures by leveraging trusted servers as proxies for malicious activity.
Source: https://gbhackers.com/cisa-warns-of-exploited-gitlab-community/
GitLab cybersecurity rating report: https://www.rankiteo.com/company/gitlab-com
Galapagos Federal Systems cybersecurity rating report: https://www.rankiteo.com/company/galapagos-federal-systems
"id": "GITGAL1770201332",
"linkid": "gitlab-com, galapagos-federal-systems",
"type": "Vulnerability",
"date": "1/2021",
"severity": "100",
"impact": "5",
"explanation": "Attack threatening the organization's existence"{'affected_entities': [{'customers_affected': 'Users of GitLab Community and '
'Enterprise Editions',
'industry': 'Technology/DevOps',
'name': 'GitLab',
'type': 'Software Provider'}],
'attack_vector': 'CI Lint API',
'customer_advisories': 'Users of GitLab Community and Enterprise Editions are '
'urged to upgrade immediately and monitor for '
'suspicious activity.',
'description': 'CISA has added CVE-2021-39935, a severe server-side request '
'forgery (SSRF) vulnerability in GitLab Community and '
'Enterprise Editions, to its Known Exploited Vulnerabilities '
'(KEV) catalog after confirming active exploitation in the '
'wild. The flaw resides in GitLab’s CI Lint API, allowing '
'unauthenticated attackers to manipulate the server into '
'making unauthorized requests to internal systems, bypass '
'perimeter defenses, access restricted resources, and '
'potentially move laterally within compromised networks. The '
'vulnerability poses risks including data exposure, supply '
'chain compromise via CI/CD pipeline manipulation, and '
'unauthorized access to cloud metadata or internal '
'infrastructure.',
'impact': {'data_compromised': 'Potential data exposure',
'operational_impact': 'Potential lateral movement within networks, '
'supply chain compromise via CI/CD pipeline '
'manipulation',
'systems_affected': 'GitLab Community and Enterprise Editions'},
'initial_access_broker': {'entry_point': 'CI Lint API'},
'lessons_learned': 'The incident highlights the growing threat of SSRF '
'attacks, which can evade traditional security measures by '
'leveraging trusted servers as proxies for malicious '
'activity.',
'motivation': ['Data exposure',
'Supply chain compromise',
'Unauthorized access to internal systems'],
'post_incident_analysis': {'corrective_actions': 'Patch management, API '
'configuration review, '
'enhanced monitoring',
'root_causes': 'SSRF vulnerability in GitLab’s CI '
'Lint API (CVE-2021-39935)'},
'recommendations': 'Upgrade immediately to patched versions, review CI Lint '
'API configurations, monitor logs for suspicious activity, '
'and adhere to BOD 22-01 guidance for securing cloud '
'services.',
'references': [{'source': 'CISA Known Exploited Vulnerabilities (KEV) '
'catalog'}],
'regulatory_compliance': {'regulatory_notifications': 'Binding Operational '
'Directive 22-01 for '
'Federal Civilian '
'Executive Branch '
'(FCEB) agencies'},
'response': {'containment_measures': 'Patch or mitigate the vulnerability, '
'discontinue use of affected instances '
'if unable to patch',
'enhanced_monitoring': 'Monitor logs for unusual API requests or '
'unexpected internal connections',
'remediation_measures': 'Upgrade to patched versions, review CI '
'Lint API configurations, monitor logs '
'for suspicious activity'},
'stakeholder_advisories': 'Federal Civilian Executive Branch (FCEB) agencies '
'must patch or mitigate the vulnerability by '
'February 24, 2026.',
'threat_actor': ['Advanced Persistent Threat (APT) groups',
'Initial Access Brokers'],
'title': 'Critical GitLab SSRF Vulnerability Under Active Exploitation, CISA '
'Warns',
'type': 'Server-Side Request Forgery (SSRF)',
'vulnerability_exploited': 'CVE-2021-39935 (CWE-918)'}