Vulnerability in Fail2ban
CVSS score
5.3
EPSS probability
—
Risk score
0.5
Published
6 h ago
Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.
Impact on My Inventory
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
1
Source agreement
Tam uyum
Evidence confidence
%55
Short explanation
The sshd filter in fail2ban versions 0.10.5 through 1.1.1 accepts an on <token> suffix after the host address, allowing attackers to associate failed login attempts with arbitrary source IPs and block them.
This vulnerability enables remote unauthenticated attackers to block legitimate users from logging in, resulting in a denial of service.
What should be done?
- Apply the fixes provided in the patch references
- Follow vendor advisory documentation
- Review fail2ban configurations
Chain of evidence and sources
Fail2ban 0.10.5 ile 1.1.1 sürümleri arasındaki sshd filtresi on <token> son ekini kabul eder.
Saldırganlar meşru kullanıcıların oturum açmasını engellemek için başarısız girişleri rastgele kaynak IP adresleriyle ilişkilendirebilir.
Bu güvenlik açığı için doğrulanmış yama referansları mevcuttur.
Show the technical text from the sources
In fail2ban 0.10.5 through 1.1.1 before ddd879d, the sshd filter (config/filter.d/sshd.conf) accepts an "on <token>" suffix after the host address. Because OpenSSH logs the offered username verbatim, a remote unauthenticated attacker can use a username such as "x VICTIM-SOURCE-IP-ADDRESS on" to make fail2ban associate failed login attempts with an arbitrary source IP address and ban it (e.g., to block logins from a legitimate user). The default filter mode is affected.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE: CWE-117
Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-109786 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | fail2ban | fail2ban | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 5.3 | CVSS V3_1 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | CVE CNA |
| 5.3 | CVSS V31 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.
Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-109786 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-109786 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Get this vulnerability through the API
Affected products, version ranges, exploitation status and patch information in a single request, with a free key.
curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-109786"