CVE-2026-26164

Status: ModifiedHigh (7.5)—

Improper neutralization of special elements used in a command ('command injection') in M365 Copilot allows an unauthorized attacker to disclose information over a network.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Base score: 7.5

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 1.03%
Percentile among all scored CVEs: 62
Score date: 10/5/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access90 %
Primary impactT1005 Data from Local Systemcollection85 %

Vector CVSS AV:N/PR:N/UI:N indica acceso remoto sin autenticación ni interacción, clasificable como T1190. CWE-74 (command injection) confirma ejecución remota. Confidentialidad alta (C:H) indica lectura de datos (T1005).

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Isolation and Sandboxing

Affected technologies (1)

Microsoft — 365 Copilot Chat

CWEs

CWE-74

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26164

Raw JSON (NVD)

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{
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          "options": [
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            },
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          ],
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          "timestamp": "2026-05-08T13:51:52.712667Z"
        }
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          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
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          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "secure@microsoft.com",
      "affectedData": [
        {
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          "product": "Microsoft 365 Copilot's Business Chat",
          "versions": [
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            }
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  "published": "2026-05-07T22:16:33.773",
  "references": [
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      "tags": [
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  ],
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    }
  ],
  "lastModified": "2026-06-17T10:25:51.017",
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      "nodes": [
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          "negate": false,
          "cpeMatch": [
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}