CVE-2021-31198: microsoft exchange_server Improper Input Validation
CVSS: 7.8v3.1HighModified
Published 11-05-2021Last modified 28-02-2025
Vulnerability summary
CVE-2021-31198 is a high (CVSS 7.8) Improper Input Validation vulnerability in microsoft exchange_server. EPSS estimates a 4.87% chance of exploitation in the next 30 days, higher than 91.9% of scored vulnerabilities.
CVSS score
7.8/10
010
High · v3.1 (CVE.org)EPSS score
4.87%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 11-05-2021PublishedVulnerability first disclosed.
- 28-02-2025Last modifiedVulnerability information updated.
Description
Microsoft Exchange Server Remote Code Execution Vulnerability
CVSS metrics
3 scores · 2 sources · 2 versionsHigh 7.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CSourcesAll 2 agree
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Medium 6.8Preferred score · NVD (NIST)
AV:N/AC:M/Au:N/C:P/I:P/A:PSourcesSingle source
EPSS trend
Probability
4.87%
Chance of exploitation in the next 30 days
Percentile
92%
Versus all other CVEs
30-day change
0.00 pp
From 4.87% on 20-09-2026
20-09-202620-10-2026
EPSS score4.87%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Affected systems
Microsoft6 products
- exchange_server2013:cumulative_update_23 | 2016:cumulative_update_19 | 2016:cumulative_update_20 | 2019:cumulative_update_8 | 2019:cumulative_update_9
- microsoft exchange server 2013 cumulative update 23≥ 15.00.0, < 15.00.1497.018
- microsoft exchange server 2016 cumulative update 19≥ 15.01.0, < 15.01.2176.014
- microsoft exchange server 2016 cumulative update 20≥ 15.01.0, < 15.01.2242.010
- microsoft exchange server 2019 cumulative update 8≥ 15.02.0, < 15.02.0792.015
1 vendor · 6 products
References
2 links
portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31198X Refsource MISCPatchVendor Advisory