CVE-2011-10029Public exploitNetwork attack vector

Unauthenticated service crash via crafted USER format string

Published Aug 20, 2025 · Updated May 15, 2026

Format-string handling in Solar FTP Server 2.1.1 and earlier allows remote attackers to crash the FTP service through a crafted USER command. The USER handler processes attacker-controlled format specifiers during string-length calculation, causing a read access violation in __output_1() within sfsservice.exe. No authentication or user interaction is required; successful exploitation stops the FTP service and denies file-transfer access until it is restarted.

CVSS severity8.7
High
EPSS probability0.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Format-string handling in Solar FTP Server 2.1.1 and earlier allows remote attackers to crash the FTP service through a crafted USER command. The USER handler processes attacker-controlled format specifiers during string-length calculation, causing a read access violation in __output_1() within sfsservice.exe. No authentication or user interaction is required; successful exploitation stops the FTP service and denies file-transfer access until it is restarted.

The record

CVE
CVE-2011-10029
Published
Aug 20, 2025
Updated
May 15, 2026
Vendor
Flexbyte Software
Product
Solar FTP Server
Classifications
CWE-134, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2025CVE publishedPublication date reported by the CVE source.
  2. May 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Flexbyte Software · Solar FTP Serverversion=0 <=2.1.1

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-134Use of Externally-Controlled Format String
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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