HighVulnerabilityLLM-specific

CVE-2026-26137: Microsoft 365 Copilot Business Chat server-side request forgery over the network

Source: NVD(opens in a new tab)
Identifier: CVE-2026-26137
Published: March 19, 2026
Record updated: October 9, 2026

Known exploitation: Not listed in the CISA Known Exploited Vulnerabilities catalog at the last check.
EPSS: 0.5%

Summary

CVE-2026-26137 is a server-side request forgery (CWE-918) in Microsoft 365 Copilot's Business Chat. According to the description, an authorized attacker over a network can use it to elevate privileges. NVD has not yet provided an assessment, and the record was published on 03/19/2026.

Mitigation

The source does not state a fix yet. Check the original advisory for updates.

Details

Scores and exploitation

CVSS score: 8.9(high)
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:L
Attack vector: network
Attack complexity: low
Privileges required: low
User interaction: required
EPSS: 0.5%Estimated probability that this CVE is exploited in the next 30 days, from the FIRST Exploit Prediction Scoring System. Read on November 4, 2026.
Disclosure date: March 19, 2026

Weaknesses and techniques

Weakness (CWE): CWE-918
Attack pattern (CAPEC): CAPEC-664

Affected

Vendors: Microsoft

Classification

Attack type: Other
Attack sophistication: Moderate
AI component targeted: API
Impact: Confidentiality,
Integrity
Labels: security

How this record was produced

Summaries, mitigations and labels on this page are generated automatically from the source. The linked source is authoritative. The source gives this advisory a description and no title, so the title above is a headline generated from the source text.

Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-26137

First tracked: March 19, 2026 at 06:07 PM ET, from NVD/CVE Database

Classifier: claude-haiku-5-5, prompt v4

Classifier confidence: 90% (self-assessed)

Topics

Coding assistants

Summary

Mitigation

Topics

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