fail2ban 0.7.4 and earlier does not properly parse sshd log files, which allows remote attackers to add arbitrary hosts to the /etc/hosts.de
fail2ban 0.7.4 and earlier does not properly parse sshd log files, which allows remote attackers to add arbitrary hosts to the /etc/hosts.deny file and cause a denial of service by adding arbitrary IP addresses to the sshd log file, as demonstrated by logging in via ssh with a login name containing certain strings with an IP address.
- Published
- Dec 6, 2006
- Updated
- Jun 16, 2026
- EPSS
- 1.8% · 78th percentile
- CWE
- —
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Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 20 / 40 · 5.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 1.8%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| fail2ban | fail2ban | cpe:2.3:a:fail2ban:fail2ban |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- fail2ban fail2banup to 0.7.4 inclusive
Same product
fail2ban: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-32749Possible RCE vulnerability in mailing action using mailutils (mail-whois)33Monitor
- CVE-2012-5642server/action.py in Fail2ban before 0.8.8 does not properly handle the content of the matches tag, which might allow remote attackers to tri31Monitor
- CVE-2007-4321fail2ban 0.8 and earlier does not properly parse sshd log files, which allows remote attackers to add arbitrary hosts to the /etc/hosts.deny29Monitor
- CVE-2013-7177config/filter.d/cyrus-imap.conf in the cyrus-imap filter in Fail2ban before 0.8.11 allows remote attackers to trigger the blocking of an arb21Monitor
- CVE-2013-7176config/filter.d/postfix.conf in the postfix filter in Fail2ban before 0.8.11 allows remote attackers to trigger the blocking of an arbitrary21Monitor
- CVE-2013-2178The apache-auth.conf, apache-nohome.conf, apache-noscript.conf, and apache-overflows.conf files in Fail2ban before 0.8.10 do not properly va21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- P · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- P
Weakness class (CWE)
—
CVSS vector
AV:N/AC:L/Au:N/C:N/I:N/A:P
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- bugs.gentoo.org/show_bug.cgi?id=157166
- secunia.com/advisories/23237
- secunia.com/advisories/24184
- security.gentoo.org/glsa/glsa-200702-05.xml
- www.securityfocus.com/bid/21469
- www.vupen.com/english/advisories/2006/4877
- exchange.xforce.ibmcloud.com/vulnerabilities/30739
Vendor advisories and official records. Exploit/PoC links are deliberately left out.