Vulnerability Report

CVE-2026-8458

Title: libcurl Negotiate authentication connection reuse vulnerability

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-8458.

CWE Category NVD-CWE-noinfo

Published Date Jul 03, 2026

Modified Date Jul 07, 2026

Exploit Status Not Found

Score 6.5 CVSS v

Exploit Probability (EPSS)

0.54%

Vulnerability Summary

CVE-2026-8458: libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different 'services'. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different services.

Impacted Vendors

haxx 1

Reference Links

https://curl.se/docs/CVE-2026-8458.html https://curl.se/docs/CVE-2026-8458.json https://hackerone.com/reports/3721183

CVSS v3.1

Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0

Severity MEDIUM

6.5

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

RAW VECTOR CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-8458 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

July 07, 2026 MODIFIED

Vulnerability data updated via NVD.

July 06, 2026 MODIFIED

Vulnerability data updated via NVD.

July 03, 2026 MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK

Complexity LOW

Privileges N/A

Interaction NONE

CVSS Vector String


                                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected Stack

No specific products linked.