Authentication Bypass by Primary Weakness in cURL - CVE-2026-3784

Vulnerability identifier: #VU123889

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-3784

CWE-ID: CWE-305

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to wrong proxy connection reuse with credentials. A remote attacker can bypass authentication and gain access to the target system.

cURL
SUSE Linux Enterprise Server 12 SP5 LTSS Extended
SUSE Linux Enterprise Server 15 SP5
SUSE Linux Enterprise Server 12 SP5
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Desktop 15
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise High Performance Computing 12
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Real Time 15
SUSE Manager Server
SUSE Manager Retail Branch Server
SUSE Manager Proxy
SUSE Linux Enterprise Micro for Rancher
SUSE Linux Enterprise Micro
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
macOS
Basesystem Module
openSUSE Leap
tvOS
iPadOS
Apple iOS
Ubuntu
openEuler
Anolis OS
watchOS
Fedora
LANTIME Operating System Firmware (LTOS)
curl (Ubuntu package)
curl-debuginfo
curl-debugsource
libcurl
libcurl-devel
curl-help
curl
libcurl4-debuginfo-32bit
libcurl4-32bit
libcurl4-debuginfo
libcurl4
curl-minimal
libcurl-minimal
curl-doc
curl (Red Hat package)
libcurl-mini4-debuginfo
libcurl4-64bit-debuginfo
libcurl4-64bit
libcurl-devel-64bit
libcurl-devel-32bit
curl-fish-completion
libcurl-devel-doc
curl-zsh-completion
curl-mini-debugsource
libcurl4-32bit-debuginfo
libcurl-mini4

Install updates from vendor's website.

cURL - update to 8.19.0
LANTIME Operating System Firmware (LTOS) - update to 7.10.009
macOS - addressed in versions 14.8.8 23J620, 15.7.8 24G824, 26.6 25G72
tvOS - update to 26.6 23L773
iPadOS - addressed in versions 18.7.10 22H374, 26.6 23G71
Apple iOS - addressed in versions 18.7.10 22H374, 26.6 23G71
watchOS - update to 26.6 23U67
curl (Ubuntu package) - addressed in versions 7.58.0-2ubuntu3.24+esm8, 7.68.0-1ubuntu2.25+esm3, 7.81.0-1ubuntu1.23, 8.5.0-2ubuntu10.8, 8.14.1-2ubuntu1.2
curl-debuginfo - update to 7.71.1-47
curl-debugsource - update to 7.71.1-47
libcurl - update to 7.71.1-47
libcurl-devel - update to 7.71.1-47
curl-help - update to 7.71.1-47
curl - update to 7.71.1-47
libcurl4-debuginfo-32bit - update to 8.0.1-11.120.1
curl-debugsource - addressed in versions 8.0.1-11.120.1, 8.14.1-150200.4.103.1, 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
libcurl4-32bit - addressed in versions 8.0.1-11.120.1, 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
libcurl4-debuginfo - addressed in versions 8.0.1-11.120.1, 8.14.1-150200.4.103.1, 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
curl - addressed in versions 8.0.1-11.120.1, 8.14.1-150200.4.103.1, 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
libcurl4 - addressed in versions 8.0.1-11.120.1, 8.14.1-150200.4.103.1, 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
libcurl-devel - addressed in versions 8.0.1-11.120.1, 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
curl-debuginfo - addressed in versions 8.0.1-11.120.1, 8.14.1-150200.4.103.1, 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
curl - update to 8.4.0-15
curl-minimal - update to 8.4.0-15
libcurl - update to 8.4.0-15
libcurl-devel - update to 8.4.0-15
libcurl-minimal - update to 8.4.0-15
curl-doc - update to 8.4.0-15
curl - addressed in versions 8.11.1-8.fc42, 8.15.0-6.fc43, 8.18.0-6.fc44
curl (Red Hat package) - update to 8.12.1-1.el10_0.10
libcurl-mini4-debuginfo - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
libcurl4-64bit-debuginfo - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
libcurl4-64bit - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
libcurl-devel-64bit - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
libcurl-devel-32bit - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
curl-fish-completion - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
libcurl-devel-doc - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
curl-zsh-completion - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
curl-mini-debugsource - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1
libcurl4-32bit-debuginfo - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1, 8.14.1-150700.7.14.1
libcurl-mini4 - addressed in versions 8.14.1-150400.5.80.1, 8.14.1-150600.4.40.1

• https://curl.se/docs/CVE-2026-3784.html

• Multiple vulnerabilities in curl
• Ubuntu update for curl
• SUSE update for curl
• SUSE update for curl
• SUSE update for curl
• SUSE update for curl
• SUSE update for curl
• openEuler update for curl
• Ubuntu update for curl
• Anolis OS update for curl
• Fedora 44 update for curl
• Fedora 43 update for curl
• Fedora 42 update for curl
• Meinberg LANTIME firmware update for third-party components
• Multiple vulnerabilities in macOS Tahoe
• Multiple vulnerabilities in macOS Sequoia
• Multiple vulnerabilities in macOS Sonoma
• Multiple vulnerabilities in iOS 26 and iPadOS 26
• Multiple vulnerabilities in Apple tvOS
• Multiple vulnerabilities in Apple watchOS
• Multiple vulnerabilities in iOS 18 and iPadOS 18
• Red Hat Enterprise Linux 10 update for curl