What is CVE-2023-43876?

CVE-2023-43876 is a medium-severity vulnerability in Octobercms October, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2023-09-28.

How severe is CVE-2023-43876?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Is CVE-2023-43876 known to be exploited?

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

XSS in Octobercms October

CVE-2023-43876

A Cross-Site Scripting (XSS) vulnerability in installation of October v.3.4.16 allows an attacker to execute arbitrary web scripts via a crafted payload injected into the dbhost field.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2023-09-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.005 (38.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 38.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.001

Affected products

Octobercms October — versions 3.4.16

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

References

github.com/sromanhu/October-CMS-Reflected-XSS---Installation/blob/main/README.md (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2023-43876?: CVE-2023-43876 is a medium-severity vulnerability in Octobercms October, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2023-09-28.
How severe is CVE-2023-43876?: Medium severity. CVSS v3 base score is 5.4 out of 10.
Is CVE-2023-43876 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.