CVE-2026-24307
CVE-2026-24307 is a critical-severity vulnerability in Microsoft 365 Copilot with a CVSS 3.x base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-1287.
Key facts
- Severity: Critical (CVSS 3.x base score 9.3)
- EPSS exploit prediction: 1% (52nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-4497
- Weakness: CWE-1287
- Affected product: Microsoft 365 Copilot
- Published:
- Last modified:
Description
Improper validation of specified type of input in M365 Copilot allows an unauthorized attacker to disclose information over a network.
Frequently asked questions
- What is CVE-2026-24307?
- Improper validation of specified type of input in M365 Copilot allows an unauthorized attacker to disclose information over a network.
- How severe is CVE-2026-24307?
- CVE-2026-24307 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
- Is CVE-2026-24307 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-24307?
- CVE-2026-24307 affects Microsoft 365 Copilot. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-24307?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2026-24307 have an EU (EUVD) identifier?
- Yes. CVE-2026-24307 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4497.
- When was CVE-2026-24307 published?
- CVE-2026-24307 was published on 2026-01-22 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:microsoft:365_copilot:-:*:*:*:*:*:*:*
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