CVE-2010-4221
CriticalPublic exploitMultiple stack-based buffer overflows in the pr_netio_telnet_gets function in netio.c in ProFTPD before 1.3.3c allow remote attackers to execute arbitrary code via vectors involving a TELNET IAC escape character to a (1) FTP or (2) FTPS server.
Published Nov 9, 2010 · Updated Aug 4, 2026 · Also known as DEBIAN-CVE-2010-4221
Key Facts
Patch immediately- CVE-2010-4221 is a critical-severity vulnerability (CVSS 10.0 v2) affecting Proftpd, proftpd-dfsg (debian).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 91% probability of exploitation in the next 30 days.
- Fixed versions are available, including proftpd-dfsg 1.3.3a-5.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v2
10.0
AV:N/AC:L/Au:N/C:C/I:C/A:C
EPSS (30-day exploit likelihood)
91%
Higher than 99.8% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2010-4221 brief as a PDF
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Description
Multiple stack-based buffer overflows in the pr_netio_telnet_gets function in netio.c in ProFTPD before 1.3.3c allow remote attackers to execute arbitrary code via vectors involving a TELNET IAC escape character to a (1) FTP or (2) FTPS server.
Affected Products
26 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| ProftpdProftpd | 1.3.2, 1.3.2-a, 1.3.2-b, 1.3.2-c, 1.3.2-d, 1.3.2-e, 1.3.2-rc3, 1.3.2-rc4 | n/a |
| proftpd-dfsgdebian | See advisory | 1.3.3a-5 |
Patched Releases
proftpd-dfsg
1.3.3a-5
Timeline
Publicly disclosed
Nov 9, 2010
Last updated
Aug 4, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
References
- advisory42052
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2010-4221
- exploithttp://bugs.proftpd.org/show_bug.cgi?id=3521
- exploitMSF proftp_telnet_iac.rb
- exploitMSF proftp_telnet_iac.rb
FAQ
Common Questions.
Multiple stack-based buffer overflows in the pr_netio_telnet_gets function in netio.c in ProFTPD before 1.3.3c allow remote attackers to execute arbitrary code via vectors involving a TELNET IAC escape character to a (1) FTP or (2) FTPS server.
Affected: Proftpd versions 1.3.2, 1.3.2-a, 1.3.2-b, 1.3.2-c, 1.3.2-d, 1.3.2-e, 1.3.2-rc3, 1.3.2-rc4; proftpd-dfsg (debian). The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
Fixed versions are available, including proftpd-dfsg 1.3.3a-5.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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