CVE-2026-58644

CRITICALPre-NVD 9.89.8
EchelonGraph scoreHIGH confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score elevated to 9.8 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2026-07-16), indicating real-world exploitation has been confirmed by US federal agencies. The CNA's CVSS baseline 9.8 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
9.8EG
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 mission impact
CISA-KEV: ExploitedEPSS PROB: 16%CVSS: 9.8Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.

CVSS v3
9.8
EG Score
9.8CRITICALhigh confidence
EG Risk
99
EG Risk 99/100

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)
Severity98% × 45%
The EG Score, 9.8 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 mission impact; Act at medium or high.
Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 mission impact and as soon as possible at medium or high.
EPSS PROB
16%
EPSS %ILE
96th
KEV
⚠ Exploited

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

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

Exploitation active (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 & forensic triage if the affected system is publicly exposed; 3 days & forensic triage if it is not.

In CISA KEV yes (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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/vulnerability/CVE-2026-58644 · 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-2026-58644

Published

July 14, 2026

Last Modified

October 8, 2026

Advisory Details (2)

Auto-updated Oct 8, 2026
⚠️ Actively exploited (CISA KEV, CISA Vulnrichment). Patch available. Sources: microsoft.
MicrosoftMentions a patch (unverified)

Security Update Guide - Microsoft Security Response Center

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58644
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-2026-58644

Vendor Advisories for CVE-2026-58644(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 71× in last 7d / 376× 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 4,696 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 4,596 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-14 05:08 UTCEG score recompute
  2. 2026-10-14 05:08 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-13 16:34 UTCEPSS rescoreEPSS 16% · 96th percentile
  4. 2026-10-13 05:16 UTCEG score recompute
  5. 2026-10-13 05:16 UTCVendor advisory
  6. 2026-10-13 05:16 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  7. 2026-10-12 15:53 UTCEG score recompute
  8. 2026-10-12 05:24 UTCVendor advisory
  9. 2026-10-12 05:24 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  10. 2026-10-12 01:02 UTCVendor advisory
  11. 2026-10-12 01:02 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-11 20:40 UTCVendor advisory
  13. 2026-10-11 20:40 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  14. 2026-10-11 19:36 UTCEG score recompute
  15. 2026-10-11 16:51 UTCEG score recompute
  16. 2026-10-11 16:18 UTCVendor advisory
  17. 2026-10-11 16:18 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-11 14:14 UTCEG score recompute
  19. 2026-10-11 13:49 UTCEPSS rescoreEPSS 16% · 96th percentile
  20. 2026-10-11 11:57 UTCEG score recompute
  21. 2026-10-11 11:57 UTCVendor advisory
  22. 2026-10-11 11:57 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-10-11 07:36 UTCVendor advisory
  24. 2026-10-11 07:36 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-11 03:15 UTCVendor advisory
Show 75 more
  1. 2026-10-11 03:15 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  2. 2026-10-10 22:53 UTCEG score recompute
  3. 2026-10-10 22:53 UTCVendor advisory
  4. 2026-10-10 22:53 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-10 20:00 UTCEPSS rescoreEPSS 16% · 96th percentile
  6. 2026-10-10 18:32 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  7. 2026-10-10 14:11 UTCVendor advisory
  8. 2026-10-10 14:11 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-10 09:50 UTCVendor advisory
  10. 2026-10-10 09:49 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  11. 2026-10-10 05:29 UTCVendor advisory
  12. 2026-10-10 05:28 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  13. 2026-10-10 01:07 UTCVendor advisory
  14. 2026-10-10 01:07 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-10-09 20:45 UTCEG score recompute
  16. 2026-10-09 20:45 UTCVendor advisory
  17. 2026-10-09 20:45 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-09 20:07 UTCEPSS rescoreEPSS 16% · 96th percentile
  19. 2026-10-09 16:24 UTCVendor advisory
  20. 2026-10-09 16:24 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-09 12:03 UTCVendor advisory
  22. 2026-10-09 12:02 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  23. 2026-10-09 07:42 UTCVendor advisory
  24. 2026-10-09 07:41 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  25. 2026-10-09 03:20 UTCVendor advisory
  26. 2026-10-09 03:20 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  27. 2026-10-08 22:59 UTCVendor advisory
  28. 2026-10-08 22:59 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  29. 2026-10-08 18:38 UTCEG score recompute
  30. 2026-10-08 18:38 UTCVendor advisory
  31. 2026-10-08 18:37 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  32. 2026-10-08 17:13 UTCEPSS rescoreEPSS 16% · 96th percentile
  33. 2026-10-08 16:02 UTCVendor advisory
  34. 2026-10-08 16:02 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  35. 2026-10-08 11:41 UTCVendor advisory
  36. 2026-10-08 11:41 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  37. 2026-10-08 07:19 UTCVendor advisory
  38. 2026-10-08 07:19 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  39. 2026-10-08 02:58 UTCEG score recompute
  40. 2026-10-08 02:58 UTCVendor advisory
  41. 2026-10-08 02:58 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  42. 2026-10-07 23:48 UTCEPSS rescoreEPSS 16% · 96th percentile
  43. 2026-10-07 22:37 UTCVendor advisory
  44. 2026-10-07 22:37 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  45. 2026-10-07 18:16 UTCVendor advisory
  46. 2026-10-07 18:16 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  47. 2026-10-07 13:55 UTCVendor advisory
  48. 2026-10-07 13:55 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  49. 2026-10-07 09:33 UTCVendor advisory
  50. 2026-10-07 09:33 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  51. 2026-10-07 05:11 UTCVendor advisory
  52. 2026-10-07 05:11 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  53. 2026-10-07 00:50 UTCVendor advisory
  54. 2026-10-07 00:49 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  55. 2026-10-06 20:27 UTCVendor advisory
  56. 2026-10-06 20:27 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  57. 2026-10-06 16:06 UTCEG score recompute
  58. 2026-10-06 16:06 UTCVendor advisory
  59. 2026-10-06 16:06 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  60. 2026-10-06 15:18 UTCEPSS rescoreEPSS 16% · 96th percentile
  61. 2026-10-06 11:45 UTCVendor advisory
  62. 2026-10-06 11:45 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  63. 2026-10-06 07:24 UTCVendor advisory
  64. 2026-10-06 07:24 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-10-06 03:02 UTCVendor advisory
  66. 2026-10-06 03:02 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  67. 2026-10-05 22:41 UTCVendor advisory
  68. 2026-10-05 22:41 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  69. 2026-10-05 18:20 UTCEG score recompute
  70. 2026-10-05 18:20 UTCVendor advisory
  71. 2026-10-05 18:20 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  72. 2026-10-05 17:43 UTCEPSS rescoreEPSS 16% · 96th percentile
  73. 2026-10-05 13:59 UTCVendor advisory
  74. 2026-10-05 13:59 UTCGHSA enrichmentGHSA-q6cq-5qpf-q237 · GitHub severity CRITICAL · GitHub CVSS 9.8
  75. 2026-10-05 09:38 UTCVendor advisory

Public detection templates

(1 reference)

A public Nuclei detection template is referenced for this CVE. A detection template checks whether a system is affected; it is not necessarily exploit code.

  • Nucleihttp/cves/2026/CVE-2026-58644.yaml
    Published Aug 14, 2026

    Microsoft SharePoint Server - WS-Federation BinaryFormatter Deserialization RCE

    Open source ↗

Frequently asked(6)

What is CVE-2026-58644?
CVE-2026-58644 is a critical-severity vulnerability; its CVE record was published on July 14, 2026. Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
When was CVE-2026-58644 made public?
CVE-2026-58644 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-2026-58644 actively exploited?
Yes. CISA added CVE-2026-58644 to the Known Exploited Vulnerabilities catalog on July 16, 2026, affecting Microsoft SharePoint. 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-2026-58644?
CVE-2026-58644 has a CVSS base score of 9.8 (the CNA's own assessment, by microsoft; NVD's own analysis pending).
Which products are affected by CVE-2026-58644?
CVE-2026-58644 affects Microsoft SharePoint.
How do I remediate CVE-2026-58644?
A fix for CVE-2026-58644 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-58644 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-58644

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