CVE-2026-21261

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

• ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
• AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.63% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 50.2% of scored records. A rank, not a probability.

NVD base score

5.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-02-10 17:51Z8 MO AGO

Last updated

2026-08-19 16:26Z2 MO AGO

Reserved

2025-12-11

Assigning CNA

microsoft

Record state

PUBLISHED

Severity

Medium (CVSS 5.5)

CNA CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

Weaknesses

• CWE-125Out-of-bounds ReadBase

Data version

5.2

Document digest

ba2d3550a013a7de2f761de572fc917ccba18818aada7db45971d618d7715f56

• msrc.microsoft.comMicrosoft Excel Information Disclosure Vulnerabilityhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21261vendor-advisorypatch