Solar FTP Server <= 2.1.1 Malformed USER Denial of Service
Published Aug 20, 2025
8.7
HIGHCVSS 4.0
EPSS 0.72%
Description
Solar FTP Server fails to properly handle format strings passed to the USER command. When a specially crafted string containing format specifiers is sent, the server crashes due to a read access violation in the __output_1() function of sfsservice.exe. This results in a denial of service (DoS) condition.
Affected products
-
- Version 0StatusaffectedConstraints<=2.1.1
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Flexbyte Software | Solar FTP Server | unaffected |
|
No data.
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
1 other source (NVD) ▾
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
PoCAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed Aug 20, 2025 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2025–2026- EPSS v4
- EPSS v5
Percentile over time
- EPSS v4
- EPSS v5
Table of values (6 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.72% (0.00723) | 52.31th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.68% (0.00675) | 47.18th | v5 (v2026.06.15) |
| Jan 16, 2026 | 49.68% (0.49682) | 97.71th | v4 (v2025.03.14) |
| Dec 20, 2025 | 58.60% (0.58597) | 98.11th | v4 (v2025.03.14) |
| Oct 8, 2025 | 48.33% (0.48331) | 97.58th | v4 (v2025.03.14) |
| Aug 21, 2025 | 0.04% (0.00045) | 13.06th | v4 (v2025.03.14) |
References (5)
- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/auxiliary/dos/windows/ftp/solarftp_user.rb exploit
- https://web.archive.org/web/20111009122553/http://solarftp.com/blog/news/solar-ftp-server-2-1-2.html vendor-advisorypatch
- https://web.archive.org/web/20111102141514/https://solarftp.com/ product
- https://www.exploit-db.com/exploits/16204 exploit
- https://www.vulncheck.com/advisories/solar-ftp-server-malformed-user-dos third-party-advisory
Change history (0)
No recorded changes yet.