What is CVE-2026-42824?
Missing authentication for critical function in M365 Copilot allows an unauthorized attacker to disclose information over a network.
The record classifies CVE-2026-42824 under weakness class CWE-77. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 123 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 6.5 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C - EPSS (FIRST)
- 0.5% probability of exploitation in the next 30 days, higher than 38.9% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 4.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-06-04, last modified 2026-06-19
Is CVE-2026-42824 being exploited?
No public exploitation evidence for CVE-2026-42824 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-06-19. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.
Affected products and versions
- Microsoft: 365 Copilot
How to fix CVE-2026-42824
Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42824. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-42824
1 tracked threat in the Threadlinqs corpus references CVE-2026-42824, either in the campaign’s CVE list or as an indicator on the campaign record.
- SearchLeak: Microsoft 365 Copilot Enterprise One-Click Data Exfiltration (CVE-2026-42824) — CRITICAL · 2026-06-15
Sources
Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.