CVE-2026-86409 stale SigV4 headers sent unintended
High 8.1
Published
Updated
Check this codebase for CVE-2026-86409 and fix it if it is affected.
What it is: CVE-2026-86409 is a high-severity vulnerability in curl, published on 20 Oct 2026.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86409 exists.
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-2026-86409/ (Markdown: https://insights.sbomify.com/CVE-2026-86409/index.md)
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-86409?
CVE-2026-86409 is a high-severity vulnerability in curl, published on 20 Oct 2026.
Official description
Setting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an `Authorization: AWS4-HMAC-SHA256` header to whatever URL isset next, leaking state information.
Weakness: CWE-201
Which versions are affected by CVE-2026-86409?
How do I fix CVE-2026-86409?
Upgrade to a fixed version.
Is CVE-2026-86409 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86409 exists.
Sources
Also known as ALPINE-CVE-2026-86409, AZL-109914, AZL-109956, AZL-110010, AZL-110160, AZL-110256 and 9 more.