What is CVE-2022-26503?

CVE-2022-26503 is a high-severity vulnerability in Microsoft Windows, classified under Deserialization of Untrusted Data. CVSS score: 7.8/10. Published 2022-03-17.

How severe is CVE-2022-26503?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2022-26503 known to be exploited?

15 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Deserialization in Microsoft Windows

CVE-2022-26503

Deserialization of untrusted data in Veeam Agent for Windows 2.0, 2.1, 2.2, 3.0.2, 4.x, and 5.x allows local users to run arbitrary code with local system privileges.

Vulnerability class: Insecure Deserialization

Published 2022-03-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (50.9th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 50.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Microsoft Windows
Veeam — versions 2.0, 2.1, 2.2

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

References

veeam.com (Vendor Advisory)
www.veeam.com/kb4289 (Vendor Advisory)

Frequently asked questions

What is CVE-2022-26503?: CVE-2022-26503 is a high-severity vulnerability in Microsoft Windows, classified under Deserialization of Untrusted Data. CVSS score: 7.8/10. Published 2022-03-17.
How severe is CVE-2022-26503?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2022-26503 known to be exploited?: 15 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.