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CVE-2026-86409

stale SigV4 headers sent unintended

N/A
Published: October 20, 2026 at 07:57 PM UTC
Updated: October 22, 2026 at 05:21 PM UTC
1 product affected across 1 vendorCurl

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Severity
N/A
Exploit prediction
EPSS 0.3%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (3)

Source: cverecord
https://curl.se/docs/CVE-2026-86409.json
Source: cverecord
https://curl.se/docs/CVE-2026-86409.html
Source: cverecord
https://hackerone.com/reports/3973135

Quick Info

StatusAWAITING ANALYSIS

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