CVE-2026-21665

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.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpacttotalSuccessful exploitation gives total 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

0.53% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 44.5% of scored records. A rank, not a probability.

NVD base score

7.7 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Deferred. 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

2026-02-23 22:34Z8 MO AGO

Last updated

2026-02-25 16:07Z8 MO AGO

Reserved

2026-01-02

Assigning CNA

hackerone

Record state

PUBLISHED

Severity

High (CVSS 7.7)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Weaknesses

• CWE-502Deserialization of Untrusted DataBase

Data version

5.2

Document digest

72ccf88f8a413fd90382d29b5ea97f56ed629fc83c2393d4a7692ba207ecbfdf

• learn.microsoft.comhttps://learn.microsoft.com/en-us/dotnet/core/compatibility/core-libraries/5.0/remoting-apis-obsolete