CVE-2026-56164
Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.
do firstApply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Can a WAF block it? No. A function is missing its authentication check. The attack requests look like normal traffic, so a WAF has nothing to match on.
Also consider: patch
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2026-56164 being exploited?
Yes. CVE-2026-56164 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2026-56164?
CVE-2026-56164 is rated Medium with a CVSS score of 5.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-56164?
Yes. A fix has been recorded for CVE-2026-56164. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-56164 affect?
CVE-2026-56164 affects microsoft:sharepoint_server. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
- affected>= 16.0.0 and < 16.0.5561.1001
- affected>= 16.0.0 and < 16.0.10417.20175
- affected>= 16.0.0 and < 16.0.19725.20434
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
public exploits
Unvetted proof-of-concept code on GitHub: 2 GitHub proofs of concept
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
cisa ssvc
- exploitation
- active
- automatable
- yes
- technical impact
- partial
Assessed by CISA 14 Jul 2026 (SSVC 2.0.3).
timeline
- 14 Jul 2026Added to CISA KEV (exploited in the wild)
- 14 Jul 2026Published · 1 day later
- 14 Jul 2026CISA SSVC assessment: exploitation active · same day later
- 15 Jul 2026First proof-of-concept repository on GitHub (unvetted) · same day later
- 17 Jul 2026CISA remediation due date (US federal agencies) · 2 days later
- 1 Nov 2026CVE record last updated · 108 days (about 4 months) later
- 2 Nov 2026Analysed by vulneraibility.com · 1 day later
- Patchmsrc.microsoft.com /update-guide/vulnerability/CVE-2026-56164
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56164
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.