CVE-2021-26735: zscaler client_connector Origin Validation Error
CVSS: 7.8v3.1HighModified
Published 23-10-2023Last modified 27-02-2025
Vulnerability summary
CVE-2021-26735 is a high (CVSS 7.8) Origin Validation Error vulnerability in zscaler client_connector. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 2.3% of scored vulnerabilities.
CVSS score
7.8/10
010
High · v3.1 (NVD)EPSS score
0.13%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 23-10-2023PublishedVulnerability first disclosed.
- 27-02-2025Last modifiedVulnerability information updated.
Description
The Zscaler Client Connector Installer and Unsintallers for Windows prior to 3.6 had an unquoted search path vulnerability. A local adversary may be able to execute code with SYSTEM privileges.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 7.8Preferred score · NVD (NIST)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HSources2 sources · 6.7–7.8
- CVE.orgCNA6.7MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:HDiffers
EPSS trend
Probability
0.13%
Chance of exploitation in the next 30 days
Percentile
2%
Versus all other CVEs
30-day change
0.00 pp
From 0.13% on 19-09-2026
19-09-202619-10-2026
EPSS score0.13%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-346Origin Validation ErrorThe product does not properly verify that the source of data or communication is valid.
- CWE-428Unquoted Search Path or ElementThe product uses a search path that contains an unquoted element, in which the element contains whitespace or other separators. This can cause the product to access resources in a parent path.
Affected systems
Zscaler1 product
- client_connector< 3.6
1 vendor · 1 product