Buffer overflow in Instar 2k+
CVE-2025-8760
A vulnerability was identified in INSTAR 2K+ and 4K 3.11.1 Build 1124. This affects the function base64_decode of the component fcgi_server. The manipulation of the argument Authorization leads to buffer overflow. It is possible to initiate the attack remotely.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.008 (54.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: +0.000
Affected products
- Instar 2k+ — versions 3.11.1 Build 1124
- Instar 4k — versions 3.11.1 Build 1124
Weakness classification (CWE)
Public proof-of-concept exploits
References
- vuldb.com/ (technical-description, vdb-entry)
- vuldb.com/ (signature, permissions-required)
- modzero.com/static/MZ-25-03_modzero_INSTAR.pdf (related)
Frequently asked questions
- What is CVE-2025-8760?
- CVE-2025-8760 is a critical-severity vulnerability in Instar 2k+, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 9.8/10. Published 2025-08-13.
- How severe is CVE-2025-8760?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2025-8760 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.