CVE-2026-87861 cross-origin reuse of a Negotiate connection
Not scored
Published
Updated
Check this codebase for CVE-2026-87861 and fix it if it is affected.
What it is: CVE-2026-87861 is a vulnerability in curl, published on 20 Oct 2026.
Exploitation: There is no known exploitation of CVE-2026-87861 in the wild and no public exploit code.
Affected product: curl. No package-level version data is available, so check the vendor advisory linked from the reference page.
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-87861/ (Markdown: https://insights.sbomify.com/CVE-2026-87861/index.md)
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-87861?
CVE-2026-87861 is a vulnerability in curl, published on 20 Oct 2026.
Official 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.
Which versions are affected by CVE-2026-87861?
How do I fix CVE-2026-87861?
Upgrade to a fixed version.
Is CVE-2026-87861 being exploited?
There is no known exploitation of CVE-2026-87861 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-87861, BELL-CVE-2026-87861, CURL-CVE-2026-87861, DEBIAN-CVE-2026-87861, GHSA-34qg-cqjx-hpwx, MINI-38ph-8pqw-2347.