What is CVE-2023-4879?

CVE-2023-4879 is a medium-severity vulnerability in Instantcms, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2023-09-10.

How severe is CVE-2023-4879?

Medium severity. CVSS v3 base score is 4.8 out of 10.

XSS in Instantcms

CVE-2023-4879

Cross-site Scripting (XSS) - Stored in GitHub repository instantsoft/icms2 prior to 2.16.1.-git.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2023-09-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (31.8th percentile), scored 2026-09-28.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 32nd percentile — 31.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.001

Affected products

Instantcms
Instantsoft Instantsoft/icms2 — versions unspecified

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

huntr.dev/bounties/7df6b167-3c39-4563-9b8a-33613e25cf27 (Exploit, Patch, Third Party Advisory, Issue Tracking)
github.com/instantsoft/icms2/commit/d0aeeaf5979fbdbf80dc3a3227d6c58442ab7487 (Patch)

Frequently asked questions

What is CVE-2023-4879?: CVE-2023-4879 is a medium-severity vulnerability in Instantcms, classified under Cross-site Scripting. CVSS score: 4.8/10. Published 2023-09-10.
How severe is CVE-2023-4879?: Medium severity. CVSS v3 base score is 4.8 out of 10.