CVE-2026-56164

CRITICALPre-NVD 5.39.0
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than the CVSS score beside it.

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-07-14), indicating real-world exploitation has been confirmed by US federal agencies. The CNA's CVSS baseline 5.3 retained for reference (NVD's own analysis pending). Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: CISA Known Exploited Vulnerabilities catalog, the CNA's CVSS, EPSS, GitHub Security Advisory
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV) — the reason this is sooner than the SSVC decision on this page at low or medium mission impact
CISA-KEV: ExploitedEPSS PROB: 1.0%CVSS: 5.3Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.

CVSS v3
5.3
EG Score
9.0CRITICALhigh confidence
EG Risk
96
EG Risk 96/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity90% × 45%
The EG Score, 9.0 of 10.
Exploitation100% × 40%
Fixed at 100% for a CISA KEV listing: EchelonGraph's rule.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Attend at low or medium mission impact; Act at high (mission-essential systems).
Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it sooner than your standard update timelines at low or medium mission impact and as soon as possible at high.
EPSS PROB
1.0%
EPSS %ILE
62nd
KEV
⚠ Exploited

SSVC (CISA's decision table, applied by EchelonGraph)Attend at low or medium mission impact; Act at high (mission-essential systems).

A fix is available. Apply it sooner than your standard update timelines at low or medium mission impact and as soon as possible at high.

Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)3 days if the affected system is publicly exposed; 14 days if it is not.

In CISA KEV yes (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

CISA required action“Apply 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.”

Quoted verbatim from CISA's Known Exploited Vulnerabilities catalog. CISA directs it at US federal civilian executive branch agencies under Binding Operational Directive (BOD) 26-04, which replaced BOD 22-01 on 10 June 2026; it is not EchelonGraph's advice. CISA's notes: https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-56164 · https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk · https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk · https://nvd.nist.gov/vuln/detail/CVE-2026-56164

Published

July 14, 2026

Last Modified

October 8, 2026

Advisory Details (2)

Auto-updated Oct 13, 2026
⚠️ Actively exploited (CISA KEV, CISA Vulnrichment). Patch available. Sources: microsoft.
Microsoft

Security Update Guide - Microsoft Security Response Center

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-56164
CISA🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-56164

Vendor Advisories for CVE-2026-56164(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 80× in last 7d / 417× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 6,214 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 6,114 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-14 10:58 UTCEG score recompute
  2. 2026-10-14 10:58 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  3. 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  4. 2026-10-13 09:09 UTCEG score recompute
  5. 2026-10-13 09:09 UTCVendor advisory
  6. 2026-10-13 09:09 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  7. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  8. 2026-10-12 15:55 UTCEG score recompute
  9. 2026-10-12 07:22 UTCVendor advisory
  10. 2026-10-12 07:21 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  11. 2026-10-12 03:27 UTCVendor advisory
  12. 2026-10-12 03:27 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  13. 2026-10-11 23:35 UTCVendor advisory
  14. 2026-10-11 23:34 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  15. 2026-10-11 19:43 UTCVendor advisory
  16. 2026-10-11 19:42 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  17. 2026-10-11 19:38 UTCEG score recompute
  18. 2026-10-11 16:53 UTCEG score recompute
  19. 2026-10-11 15:50 UTCVendor advisory
  20. 2026-10-11 15:50 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  21. 2026-10-11 14:16 UTCEG score recompute
  22. 2026-10-11 13:49 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  23. 2026-10-11 11:59 UTCEG score recompute
  24. 2026-10-11 11:59 UTCVendor advisory
  25. 2026-10-11 11:59 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
Show 75 more
  1. 2026-10-11 08:07 UTCVendor advisory
  2. 2026-10-11 08:07 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  3. 2026-10-11 04:16 UTCVendor advisory
  4. 2026-10-11 04:15 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  5. 2026-10-11 00:22 UTCVendor advisory
  6. 2026-10-11 00:22 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  7. 2026-10-10 20:31 UTCEG score recompute
  8. 2026-10-10 20:31 UTCVendor advisory
  9. 2026-10-10 20:31 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  10. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  11. 2026-10-10 16:39 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  12. 2026-10-10 12:48 UTCVendor advisory
  13. 2026-10-10 12:48 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  14. 2026-10-10 08:55 UTCVendor advisory
  15. 2026-10-10 08:55 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  16. 2026-10-10 05:03 UTCVendor advisory
  17. 2026-10-10 05:03 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  18. 2026-10-10 01:12 UTCVendor advisory
  19. 2026-10-10 01:12 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  20. 2026-10-09 21:19 UTCEG score recompute
  21. 2026-10-09 21:19 UTCVendor advisory
  22. 2026-10-09 21:19 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  23. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  24. 2026-10-09 17:27 UTCVendor advisory
  25. 2026-10-09 17:27 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  26. 2026-10-09 13:34 UTCVendor advisory
  27. 2026-10-09 13:33 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  28. 2026-10-09 09:43 UTCVendor advisory
  29. 2026-10-09 09:42 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  30. 2026-10-09 05:50 UTCVendor advisory
  31. 2026-10-09 05:49 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  32. 2026-10-09 01:58 UTCVendor advisory
  33. 2026-10-09 01:58 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  34. 2026-10-08 22:07 UTCVendor advisory
  35. 2026-10-08 22:07 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  36. 2026-10-08 18:15 UTCEG score recompute
  37. 2026-10-08 18:15 UTCVendor advisory
  38. 2026-10-08 18:14 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  39. 2026-10-08 17:13 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  40. 2026-10-08 15:20 UTCVendor advisory
  41. 2026-10-08 15:20 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  42. 2026-10-08 11:28 UTCVendor advisory
  43. 2026-10-08 11:28 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  44. 2026-10-08 07:37 UTCVendor advisory
  45. 2026-10-08 07:36 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  46. 2026-10-08 03:46 UTCVendor advisory
  47. 2026-10-08 03:45 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  48. 2026-10-07 23:54 UTCEG score recompute
  49. 2026-10-07 23:54 UTCVendor advisory
  50. 2026-10-07 23:54 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  51. 2026-10-07 23:48 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
  52. 2026-10-07 20:03 UTCVendor advisory
  53. 2026-10-07 20:03 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  54. 2026-10-07 16:12 UTCVendor advisory
  55. 2026-10-07 16:11 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  56. 2026-10-07 12:20 UTCVendor advisory
  57. 2026-10-07 12:20 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  58. 2026-10-07 08:29 UTCVendor advisory
  59. 2026-10-07 08:29 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  60. 2026-10-07 04:38 UTCVendor advisory
  61. 2026-10-07 04:38 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  62. 2026-10-07 00:47 UTCVendor advisory
  63. 2026-10-07 00:46 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  64. 2026-10-06 20:55 UTCVendor advisory
  65. 2026-10-06 20:54 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  66. 2026-10-06 17:03 UTCEG score recompute
  67. 2026-10-06 17:03 UTCVendor advisory
  68. 2026-10-06 17:03 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  69. 2026-10-06 15:18 UTCEPSS rescoreEPSS 1.0% · 61st percentile
  70. 2026-10-06 13:12 UTCVendor advisory
  71. 2026-10-06 13:12 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  72. 2026-10-06 09:20 UTCVendor advisory
  73. 2026-10-06 09:20 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3
  74. 2026-10-06 05:29 UTCVendor advisory
  75. 2026-10-06 05:29 UTCGHSA enrichmentGHSA-hc2f-r46j-4w6x · GitHub CVSS 5.3

Publicly available exploits

(2 references)

Public exploit code is referenced for this CVE (2 GitHub PoCs). Defenders should treat patch urgency accordingly.

  • GitHub PoCsam00/POC-CVE-2026-56164-exploit
    Published Aug 6, 2026

    CVE-2026-56164 is a critical missing-authentication vulnerability affecting on-premises Microsoft SharePoint Server. It allows unauthenticated, remote attackers to elevate privileges over a network.

    Open source ↗
  • GitHub PoCsentinel-aidefense/CVE-2026-56164-EXP
    Published Jul 15, 2026

    CVE-2026-56164 EOP Exploit

    Open source ↗

Frequently asked(6)

What is CVE-2026-56164?
CVE-2026-56164 is a critical-severity vulnerability; its CVE record was published on July 14, 2026. Missing authentication for critical function in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.
When was CVE-2026-56164 made public?
CVE-2026-56164 was made public on July 14, 2026: that is the date its CVE record's CNA, Microsoft Corporation, gives for when the vulnerability was made public. The CVE record itself was published on July 14, 2026. EchelonGraph's copy of the record carries a last-modified date of October 8, 2026; the record at its source may have been updated since.
Is CVE-2026-56164 actively exploited?
Yes. CISA added CVE-2026-56164 to the Known Exploited Vulnerabilities catalog on July 14, 2026, affecting Microsoft SharePoint Server. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate attention. A fix is available. Apply it.
What is the CVSS score of CVE-2026-56164?
CVE-2026-56164 has a CVSS base score of 5.3 (the CNA's own assessment, by microsoft; NVD's own analysis pending). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0 (CRITICAL).
Which products are affected by CVE-2026-56164?
CVE-2026-56164 affects Microsoft SharePoint Server.
How do I remediate CVE-2026-56164?
A fix for CVE-2026-56164 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-56164 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-56164

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Is Your Infrastructure Affected by CVE-2026-56164?

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