CVE-2019-3822: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 12.9% chance of exploitation in the next 30 days.

libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow. The function creating an outgoing NTLM type-3 header (`lib/vauth/ntlm.c:Curl_auth_create_ntlm_type3_message()`), generates the request HTTP header contents based on previously received data. The check that exists to prevent the local buffer from getting overflowed is implemented wrongly (using unsigned math) and as such it does not prevent the overflow from happening. This output data can grow larger than the local buffer if very large 'nt response' data is extracted from a previous NTLMv2 header provided by the malicious or broken HTTP server. Such a 'large value' needs to be around 1000 bytes or more. The actual payload data copied to the target buffer comes from the NTLMv2 type-2 response header.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 18.10 only
• Debian Debian Linux: version 9.0 only
• Haxx Libcurl: from 7.36.0, before 7.64.0 (fixed in 7.64.0)
• Netapp Active Iq Unified Manager: from 7.3; from 9.5
• Netapp Clustered Data Ontap: any version
• Netapp Oncommand Insight: affected versions not specified
• Netapp Oncommand Workflow Automation: affected versions not specified
• Netapp Snapcenter: affected versions not specified
• Oracle Communications Operations Monitor: version 3.4 only; version 4.0 only
• Oracle Enterprise Manager Ops Center: version 12.3.3 only; version 12.4.0 only
• Oracle HTTP Server: version 12.2.1.3.0 only
• Oracle MySQL Server: up to and including 5.7.26; from 5.7.27, up to and including 8.0.15
• Oracle Secure Global Desktop: version 5.4 only
• Oracle Services Tools Bundle: version 19.2 only
• Red Hat Enterprise Linux: version 8.0 only
• Siemens Sinema Remote Connect Client: up to and including 2.0

Published 2019-02-06. Last modified 2026-06-17.