Unknown

CVE-2026-86413 — Negotiate credentials sent to redirected origin

When using an *ambient user* in a first transfer doing Negotiate authentication and asked to follow redirects, curl could pass on its credential details to an unrelated second origin when asked to redirect there.

Published Oct 20, 2026 · Updated Oct 20, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: curl

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

No scoring signals.

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Curl

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Curl Curl).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Curl	Curl	≥ 8.22.0 and ≤ 8.22.0≥ 8.21.0 and ≤ 8.21.0	Vulnerable	CVE Program (cve.org) e CISA ADP

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 20, 2026
Affected products added · curl/curl
Oct 20, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 20, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 20, 2026 · Alertas do Telegram
CVE published
Oct 20, 2026 · curl

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 20, 2026 – Oct 20, 2026
1× Official description updated · Oct 20, 2026 – Oct 20, 2026

References

3 on the record

hackerone.com/reports/3993549
NIST National Vulnerability Database
curl.se/docs/CVE-2026-86413.json
NIST National Vulnerability Database
curl.se/docs/CVE-2026-86413.html
NIST National Vulnerability Database

Elsewhere on this site

Curl
every CVE for this vendor

Related CVEs (same products)

Unknown CVE-2026-94265 Authorization: Negotiate sent to foreign origin 1d
Unknown CVE-2026-94266 password leak in CURLINFO_EFFECTIVE_URL 1d
Unknown CVE-2026-92391 curl_mime_free stack overflow by recursion 1d
Unknown CVE-2026-92388 FTP wildcard write callback mixup 1d
Unknown CVE-2026-92390 -J no-clobber guarantee bypassed with 103 early hints 1d
Unknown CVE-2026-92389 TFTP direction confusion 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-86413 is "Negotiate credentials sent to redirected origin", rated Unknown. It affects Curl (Curl); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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