How severe is CVE-2026-83674?

CVE-2026-83674 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-83674?

Affected package information for CVE-2026-83674 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-83674?

No fixed release is recorded for CVE-2026-83674 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

How do I detect CVE-2026-83674 in my code and dependencies?

Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

How do I mitigate CVE-2026-83674 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-83674 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-83674 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is CVE-2026-83674?

CVE-2026-83674 is classified as CWE-1390 (CWE-1390). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-83674 published, and has it been updated?

CVE-2026-83674 was published on October 13, 2026 and was last updated on October 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🛡️

Not in CISA KEV

HIGH severity

CVE-2026-83674 — Microsoft

HIGH

CVE-2026-83674 is a high-severity (CVSS 8.1) CWE-1390 vulnerability. No vendor fix is recorded yet; mitigation options are listed below.

Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.

Published

Oct 13, 2026

Updated

Oct 13, 2026

Affected

—

Patched

—

Exploits

None indexed

Exploitation data as of Oct 13, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Description

Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.

Detection & mitigation playbook

Vulnerability

Detect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2026-83674 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to perform spoofing over a network.

O3 Security · Impact-Aware SCA

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CVE-2026-83674 — Microsoft

Description

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

Frequently Asked Questions

Is CVE-2026-83674 in your dependencies?