Skip to main content

curl CVE-2026-5545

| EUVDEUVD-2026-29923 MEDIUM
Insufficient Session Expiration (CWE-613)
6.5
CVSS 3.1 · NVD
Share

Severity by source

NVD PRIMARY
6.5 MEDIUM
AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N
SUSE
MEDIUM
qualitative
Red Hat
6.5 MEDIUM
qualitative

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
High
Availability
None

Lifecycle Timeline

3
Analysis Generated
Jun 08, 2026 - 11:20 vuln.today
CVSS changed
May 13, 2026 - 18:22 NVD
6.5 (MEDIUM)
CVE Published
May 08, 2026 - 06:45 nvd
UNKNOWN (no severity yet)

Description PRE-NVD

Disclosed via oss-security. NVD scoring and full description are pending.

AnalysisAI

Wrong reuse of HTTP Negotiate-authenticated connections in curl exposes a high-integrity-impact vulnerability where subsequent HTTP requests may inherit an authentication context they should not, potentially allowing requests to be dispatched under incorrect Negotiate (Kerberos/NTLM/SPNEGO) credentials. Affecting an extraordinarily broad version range - curl 7.10.6 through at least 8.19.0 per EUVD data - this flaw was coordinated and disclosed by curl maintainer Daniel Stenberg via oss-security on 2026-04-29 alongside three related connection-reuse CVEs. No public exploit code has been identified and no active exploitation has been confirmed; a vendor-released patch is available, with downstream fixes confirmed by Red Hat (RHSA-2026:12916) and SUSE.

Technical ContextAI

curl (CPE: cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*) implements connection pooling and reuse as a core performance optimization: rather than tearing down and re-establishing TCP/TLS connections for each request, connections are cached and reused across transfers. HTTP Negotiate authentication (RFC 4559) is a SPNEGO-based scheme that wraps Kerberos or NTLM, negotiating a session-level security context over the connection itself rather than per-request. CWE-613 (Insufficient Session Expiration) is the root cause class: when curl pools a connection that carried a Negotiate authentication handshake, it fails to properly enforce that the negotiated security context is no longer valid or applicable when the connection is later reused for a different request - effectively treating a session-bound credential exchange as perpetually reusable. This is structurally similar to the sibling CVE-2026-5773 (SMB connection reuse) and CVE-2026-4873 (TLS requirement bypass on reuse) disclosed in the same coordinated batch, suggesting a systemic pattern in curl's connection-reuse logic across protocols.

RemediationAI

The primary remediation is to upgrade curl to the patched version released by the curl project; the exact fixed version should be confirmed at https://curl.se/docs/CVE-2026-5545.html, as no specific fixed version number is independently confirmed in the available intelligence data. Red Hat Enterprise Linux users should apply RHSA-2026:12916 via standard package management; SUSE users should apply the relevant SUSE-SU advisory for their distribution version. If an immediate upgrade is not feasible in environments using HTTP Negotiate authentication, a compensating control is to disable connection reuse explicitly in curl (via CURLOPT_FORBID_REUSE set to 1L in libcurl, or --no-keepalive in the curl CLI) - note this carries a performance cost as each request will require a full connection establishment. Alternatively, avoid HTTP Negotiate authentication entirely where Kerberos or NTLM is not strictly required, substituting token-based or certificate-based auth that is not session-bound to the connection. Monitoring curl usage in environments with enterprise authentication (Active Directory, MIT Kerberos) for anomalous cross-user request patterns is advisable until patching is complete.

More in Curl

View all
CVE-2013-0249 HIGH POC
7.5 Mar 08

Stack-based buffer overflow in the Curl_sasl_create_digest_md5_message function in lib/curl_sasl.c in curl and libcurl 7

CVE-2015-3145 HIGH
7.5 Apr 24

The sanitize_cookie_path function in cURL and libcurl 7.31.0 through 7.41.0 does not properly calculate an index, which

CVE-2022-32221 CRITICAL POC
9.8 Dec 05

When doing HTTP(S) transfers, libcurl might erroneously use the read callback (`CURLOPT_READFUNCTION`) to ask for data t

CVE-2022-32207 CRITICAL POC
9.8 Jul 07

When curl < 7.84.0 saves cookies, alt-svc and hsts data to local files, it makes the operation atomic by finalizing the

CVE-2018-0500 CRITICAL POC
9.8 Jul 11

Curl_smtp_escape_eob in lib/smtp.c in curl 7.54.1 to and including curl 7.60.0 has a heap-based buffer overflow that mig

CVE-2023-23914 CRITICAL POC
9.1 Feb 23

A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functional

CVE-2023-27534 HIGH POC
8.8 Mar 30

A path traversal vulnerability exists in curl <8.0.0 SFTP implementation causes the tilde (~) character to be wrongly re

CVE-2023-27533 HIGH POC
8.8 Mar 30

A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an atta

CVE-2025-0665 HIGH POC
7.0 Feb 05

A double-close vulnerability exists in libcurl when tearing down connection channels after threaded name resolution, cau

CVE-2022-27778 HIGH POC
8.1 Jun 02

A use of incorrectly resolved name vulnerability fixed in 7.83.1 might remove the wrong file when `--no-clobber` is used

CVE-2021-22901 HIGH POC
8.1 Jun 11

curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when

CVE-2020-8177 HIGH POC
7.8 Dec 14

curl 7.20.0 through 7.70.0 is vulnerable to improper restriction of names for files and other resources that can lead to

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
Container suse/manager/4.3/proxy-httpd:4.3.17.9.76.18 Container suse/manager/4.3/proxy-salt-broker:4.3.17.9.66.20 Container suse/sle-micro-rancher/5.3:latest Container suse/sle-micro-rancher/5.4:5.4.4.5.106 Container suse/sle-micro/5.3/toolbox:16.3-6.11.222 Container suse/sle-micro/5.4/toolbox:16.3-5.19.222 Container suse/sle-micro/5.5/toolbox:16.3-3.12.133 Container suse/sle-micro/base-5.5:2.0.4-5.8.271 Image SLES15-SP4-BYOS Image SLES15-SP4-BYOS-Azure Image SLES15-SP4-BYOS-EC2 Image SLES15-SP4-BYOS-GCE Image SLES15-SP4-CHOST-BYOS Image SLES15-SP4-CHOST-BYOS-Aliyun Image SLES15-SP4-CHOST-BYOS-Azure Image SLES15-SP4-CHOST-BYOS-EC2 Image SLES15-SP4-CHOST-BYOS-GCE Image SLES15-SP4-CHOST-BYOS-SAP-CCloud Image SLES15-SP4-HPC-BYOS Image SLES15-SP4-HPC-BYOS-Azure Image SLES15-SP4-HPC-BYOS-EC2 Image SLES15-SP4-HPC-BYOS-GCE Image SLES15-SP4-HPC-EC2 Image SLES15-SP4-HPC-GCE Image SLES15-SP4-Hardened-BYOS Image SLES15-SP4-Hardened-BYOS-Azure Image SLES15-SP4-Hardened-BYOS-EC2 Image SLES15-SP4-Hardened-BYOS-GCE Image SLES15-SP4-SAP-BYOS Image SLES15-SP4-SAP-BYOS-Azure Image SLES15-SP4-SAP-BYOS-EC2 Image SLES15-SP4-SAP-BYOS-GCE Image SLES15-SP4-SAP-Hardened Image SLES15-SP4-SAP-Hardened-Azure Image SLES15-SP4-SAP-Hardened-BYOS Image SLES15-SP4-SAP-Hardened-BYOS-Azure Image SLES15-SP4-SAP-Hardened-BYOS-EC2 Image SLES15-SP4-SAP-Hardened-BYOS-GCE Image SLES15-SP4-SAP-Hardened-GCE Image SLES15-SP5-BYOS-Azure Image SLES15-SP5-BYOS-EC2 Image SLES15-SP5-BYOS-GCE Image SLES15-SP5-CHOST-BYOS-Aliyun Image SLES15-SP5-CHOST-BYOS-Azure Image SLES15-SP5-CHOST-BYOS-EC2 Image SLES15-SP5-CHOST-BYOS-GCE Image SLES15-SP5-CHOST-BYOS-GDC Image SLES15-SP5-CHOST-BYOS-SAP-CCloud Image SLES15-SP5-EC2 Image SLES15-SP5-GCE Image SLES15-SP5-HPC-BYOS-Azure Image SLES15-SP5-HPC-BYOS-EC2 Image SLES15-SP5-HPC-BYOS-GCE Image SLES15-SP5-Hardened-BYOS-Azure Image SLES15-SP5-Hardened-BYOS-EC2 Image SLES15-SP5-Hardened-BYOS-GCE Image SLES15-SP5-SAP-Azure-3P Image SLES15-SP5-SAP-BYOS-Azure Image SLES15-SP5-SAP-BYOS-EC2 Image SLES15-SP5-SAP-BYOS-GCE Image SLES15-SP5-SAP-Hardened-Azure Image SLES15-SP5-SAP-Hardened-BYOS-Azure Image SLES15-SP5-SAP-Hardened-BYOS-EC2 Image SLES15-SP5-SAP-Hardened-BYOS-GCE Image SLES15-SP5-SAP-Hardened-GCE Affected
Container suse/sl-micro/6.0/baremetal-os-container:2.1.3-6.172 Container suse/sl-micro/6.0/kvm-os-container:2.1.3-6.155 Container suse/sl-micro/6.0/rt-os-container:2.1.3-7.168 Affected
Container suse/sl-micro/6.0/base-os-container:2.1.3-7.139 Container suse/sl-micro/6.0/toolbox:13.2-9.105 Image SL-Micro Affected
Container suse/sl-micro/6.1/baremetal-os-container:2.2.1-7.102 Container suse/sl-micro/6.1/kvm-os-container:2.2.1-5.127 Container suse/sl-micro/6.1/rt-os-container:2.2.1-5.116 Affected
Container suse/sl-micro/6.1/base-os-container:2.2.1-5.126 Image SL-Micro-Azure Image SL-Micro-BYOS-Azure Image SL-Micro-BYOS-EC2 Image SL-Micro-BYOS-GCE Image SL-Micro-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-Azure Image SUSE-Multi-Linux-Manager-Proxy-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Proxy-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-Azure-llc Image SUSE-Multi-Linux-Manager-Server-Azure-ltd Image SUSE-Multi-Linux-Manager-Server-BYOS-Azure Image SUSE-Multi-Linux-Manager-Server-BYOS-EC2 Image SUSE-Multi-Linux-Manager-Server-BYOS-GCE Image SUSE-Multi-Linux-Manager-Server-EC2-llc Image SUSE-Multi-Linux-Manager-Server-EC2-ltd Affected

Share

CVE-2026-5545 vulnerability details – vuln.today

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy