CVE-2026-87861
cross-origin reuse of a Negotiate connection
Description
When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's intended credentials unused.
INFO
Published Date :
Oct. 20, 2026, 9:17 p.m.
Last Modified :
Oct. 20, 2026, 9:17 p.m.
Remotely Exploit :
No
Source :
2499f714-1537-4658-8207-48ae4bb9eae9
Solution
- Disable delegation of ambient user credentials.
- Configure requests to use explicit, intended credentials.
- Review authentication and session management configurations.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-87861.
| URL | Resource |
|---|---|
| https://curl.se/docs/CVE-2026-87861.html | |
| https://curl.se/docs/CVE-2026-87861.json | |
| https://hackerone.com/reports/3972094 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-87861 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-87861
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-87861 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-87861 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 2499f714-1537-4658-8207-48ae4bb9eae9
Oct. 20, 2026
Action Type Old Value New Value Added Description When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's intended credentials unused. Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/87xxx/CVE-2026-87861.json">CVE-2026-87861</a> Added Reference https://curl.se/docs/CVE-2026-87861.html Added Reference https://curl.se/docs/CVE-2026-87861.json Added Reference https://hackerone.com/reports/3972094