CVE-2026-86409
highSetting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication, contrary to expectations and documentation.
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.
CVSS
8.1
8.1 (CVSS v3.1)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
Timeline (UTC)
Published: 2026-10-20 20:17
Modified: 2026-10-29 19:17
NVD status: Awaiting Analysis
Last synced 5 days ago
Verified against the source API 2026-10-30 08:34 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
Not reported by the source (unknown — not "none").
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
No vendor advisory or patch reference tagged by NVD. Check the references below.
References
- https://curl.se/docs/CVE-2026-86409.html 2499f714-1537-4658-8207-48ae4bb9eae9
- https://curl.se/docs/CVE-2026-86409.json 2499f714-1537-4658-8207-48ae4bb9eae9
- https://hackerone.com/reports/3973135 2499f714-1537-4658-8207-48ae4bb9eae9
- https://hackerone.com/reports/3973135 134c704f-9b21-4f2e-91b3-4a467353bcc0
Data sources
NVD CVE API 2.0 — fetched 2026-10-30 08:34 UTC · record ↗