CVE-2026-86409LowNetworkRevised 4 Nov

stale SigV4 headers sent unintended

MSRC advisory NVD CVE.org

Assessment

Severity: Low
CVSS base score: 3.7CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Impact: Not stated
EPSS · 30-day forecast: No EPSS score collected
Public detection template: No Nuclei template is listed in the current collected catalog
Exploitation detected: Unknown: not stated by MSRC
Exploitability: Not assessed
Publicly disclosed: Unknown: not stated by MSRC
Customer action: Required: follow the MSRC remediation guidance
Component: Mariner
Weakness: —
Issued by: curl
Published: 23 Oct 2026 · October 2026
Last revised: 4 Nov 2026Information published.

CVSS 3.1 base metricsRed raises the risk · green lowers it

Attack vector: NetworkAV:N
Attack complexity: HighAC:H
Privileges required: NonePR:N
User interaction: NoneUI:N
Scope: UnchangedS:U
Confidentiality: LowC:L
Integrity: NoneI:N
Availability: NoneA:N

Updates that fix it

0 KBs

No KB listed

No KB update is listed in the collected MSRC record. Check the MSRC advisory for product releases and other remedies.

Affected products

Open Source Software

1 affected product

azl3 curl 8.11.1-12 on Azure Linux 3.0

What changed

Detection template: Unknown: detection-template evidence is incomplete or retained → No Nuclei template listed
6 Nov 2026 · 17:32:22 UTC
Detection template: No Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
6 Nov 2026 · 16:31:02 UTC

Page history

Changes are dated when recorded; day views use the last saved version from that UTC day, and citations stay fixed.

Cite this version

Field-level log (8)

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6 Nov 2026 · 17:32:22 UTC Public detection templateUnknown: detection-template evidence is incomplete or retained → No Nuclei template listed
6 Nov 2026 · 17:32:22 UTC Source coverage: public-exploit-codeIncomplete → Current
6 Nov 2026 · 17:32:22 UTC Source coverage: first-epssIncomplete → Current
6 Nov 2026 · 17:32:22 UTC Source coverage: msrc-cvrfIncomplete → Current
6 Nov 2026 · 16:31:02 UTC Public detection templateNo Nuclei template listed → Unknown: detection-template evidence is incomplete or retained
6 Nov 2026 · 16:31:02 UTC Source coverage: public-exploit-codeCurrent → Incomplete
6 Nov 2026 · 16:31:02 UTC Source coverage: first-epssCurrent → Incomplete
6 Nov 2026 · 16:31:02 UTC Source coverage: msrc-cvrfCurrent → Incomplete

Explore global source statements, affected packages and advisory history for CVE-2026-86409. The catalog has a separate collection scope from Microsoft release records.

Collected exploitation and prediction evidence

Risk source coverage

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-86409

Published

stale SigV4 headers sent unintended

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.

Source published: 20 Oct 2026 19:57:01 UTC
Source modified: 29 Oct 2026 18:33:49 UTC
Observed here: 29 Oct 2026 19:28:49 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.