Exposure of Data Element to Wrong Session in cURL - CVE-2026-8458

Vulnerability identifier: #VU135076

CSH Severity: Low

CVSS v4: 2.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-8458

CWE-ID: CWE-488

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote user to expose data to the wrong session.

The vulnerability exists due to exposure of data element to wrong session in libcurl connection reuse logic when reusing Negotiate-authenticated connections across different services. A remote user can issue a request that wrongfully reuses an existing authenticated connection to expose data to the wrong session.

The issue only occurs when using the same hostname, port number, and credentials, and when the previous connection remains alive in the connection pool.

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

Install security update from vendor's website.

cURL - update to 8.21.0
LANTIME Operating System Firmware (LTOS) - update to 7.10.013
Red Hat OpenShift Dev Spaces - update to 3.30.1
curl (Ubuntu package) - addressed in versions 7.35.0-1ubuntu2.20+esm20, 7.35.0-1ubuntu2.20+esm23, 7.47.0-1ubuntu2.19+esm16, 7.58.0-2ubuntu3.24+esm9, 7.68.0-1ubuntu2.25+esm4, 7.81.0-1ubuntu1.25, 8.5.0-2ubuntu10.10, 8.14.1-2ubuntu1.4, 8.18.0-1ubuntu2.2
curl - addressed in versions 7.71.1-52, 7.79.1-53, 8.4.0-35
curl-debuginfo - addressed in versions 7.71.1-52, 7.79.1-53, 8.4.0-35
curl-debugsource - addressed in versions 7.71.1-52, 7.79.1-53, 8.4.0-35
curl-help - addressed in versions 7.71.1-52, 7.79.1-53, 8.4.0-35
libcurl-devel - addressed in versions 7.71.1-52, 7.79.1-53, 8.4.0-35
libcurl - addressed in versions 7.71.1-52, 7.79.1-53, 8.4.0-35
libcurl4-debuginfo - addressed in versions 8.0.1-11.126.1, 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
curl-debugsource - addressed in versions 8.0.1-11.126.1, 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
curl - addressed in versions 8.0.1-11.126.1, 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
libcurl-devel - addressed in versions 8.0.1-11.126.1, 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
libcurl4-debuginfo-32bit - update to 8.0.1-11.126.1
libcurl4 - addressed in versions 8.0.1-11.126.1, 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
curl-debuginfo - addressed in versions 8.0.1-11.126.1, 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
libcurl4-32bit - addressed in versions 8.0.1-11.126.1, 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
curl (Red Hat package) - update to 8.12.1-1.el10_0.10
libcurl-devel-64bit - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
libcurl4-64bit - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
libcurl4-32bit-debuginfo - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1, 8.14.1-150700.7.20.1
libcurl-mini4 - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
libcurl-mini4-debuginfo - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
libcurl-devel-32bit - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
curl-zsh-completion - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
libcurl-devel-doc - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
curl-fish-completion - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
libcurl4-64bit-debuginfo - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
curl-mini-debugsource - addressed in versions 8.14.1-150400.5.86.1, 8.14.1-150600.4.46.1
curl - addressed in versions 8.15.0-10.fc43, 8.18.0-10.fc44

• https://curl.se/docs/CVE-2026-8458.html
• https://github.com/curl/curl/commit/5e99b73cf441d9c369768b9cd

• Multiple vulnerabilities in cURL
• Ubuntu update for curl
• SUSE update for curl
• SUSE update for curl
• SUSE update for curl
• Multiple vulnerabilities in Meinberg LANTIME firmware
• SUSE update for curl
• openEuler 24.03 LTS SP3 update for curl
• openEuler 24.03 LTS SP1 update for curl
• openEuler 22.03 LTS SP4 update for curl
• openEuler 20.03 LTS SP4 update for curl
• Fedora 44 update for curl
• Fedora 43 update for curl
• openEuler 24.03 LTS SP4 update for curl
• Red Hat Enterprise Linux 10 update for curl
• Multiple vulnerabilities in Red Hat OpenShift Dev Spaces 3.30
• Ubuntu update for curl