CVE-2023-28807: zscaler secure_internet_and_saas_access Improper Certificate Validation
CVSS: 7.5v3.1HighModified
Published 31-01-2024Last modified 17-06-2025
Vulnerability summary
CVE-2023-28807 is a high (CVSS 7.5) Improper Certificate Validation vulnerability in zscaler secure_internet_and_saas_access. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 26.5% of scored vulnerabilities.
CVSS score
7.5/10
010
High · v3.1 (NVD)EPSS score
0.34%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 31-01-2024PublishedVulnerability first disclosed.
- 17-06-2025Last modifiedVulnerability information updated.
Description
In Zscaler Internet Access (ZIA) a mismatch between Connect Host and Client Hello's Server Name Indication (SNI) enables attackers to evade network security controls by hiding their communications within legitimate traffic.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 7.5Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NSources2 sources · 5.1–7.5
- CVE.orgCNA5.1MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NDiffers
EPSS trend
Probability
0.34%
Chance of exploitation in the next 30 days
Percentile
27%
Versus all other CVEs
30-day change
0.00 pp
From 0.34% on 19-09-2026
19-09-202619-10-2026
EPSS score0.34%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Zscaler2 products
- secure_internet_and_saas_access< 6.2r.290
- zia< 6.2r.290
1 vendor · 2 products