What is CVE-2023-4649?

CVE-2023-4649 is a medium-severity vulnerability in Instantcms, classified under Session Fixation. CVSS score: 5.4/10. Published 2023-08-31.

How severe is CVE-2023-4649?

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

Vulnerability in Instantcms

CVE-2023-4649

Session Fixation in GitHub repository instantsoft/icms2 prior to 2.16.1.

Published 2023-08-31 · 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:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (35.6th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 35.6% 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: 0.004 · change: +0.001

Affected products

Instantcms
Instantsoft Instantsoft/icms2 — versions unspecified

Weakness classification (CWE)

CWE-384 — Session Fixation

References

huntr.dev/bounties/069bb1f3-0805-480d-a6e1-b3345cdc60f3 (Exploit, Patch, Third Party Advisory)
github.com/instantsoft/icms2/commit/ca5f150da11d9caae86638885137afe35bcc3592 (Patch)

Frequently asked questions

What is CVE-2023-4649?: CVE-2023-4649 is a medium-severity vulnerability in Instantcms, classified under Session Fixation. CVSS score: 5.4/10. Published 2023-08-31.
How severe is CVE-2023-4649?: Medium severity. CVSS v3 base score is 5.4 out of 10.