PatchTheCEVCVE-2026-86409: Setting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication, contrary to expectations and do
9
Routine
HIGH n/aWATCHLIST
CVE-2026-86409 is a high-severity flaw (CVSS n/a) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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.
Why this priority
- On your watchlist
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | n/a (High) |
| EPSS exploit chance | 0.2% (top 85%) |
| CISA exploited list | No |
| Published | 2026-10-20 |
| Last modified | 2026-10-22 |
Publisher (CNA): curl
Timeline
- Published CVE record published
- Updated Record last modified
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Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.