CVE-2026-44183
Published: 12 May 2026
Summary
CVE-2026-44183 is a critical-severity Authentication Bypass by Spoofing (CWE-290) vulnerability. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 12.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-29725
Vulnerability details
Cleanuparr is a tool for automating the cleanup of unwanted or blocked files in Sonarr, Radarr, and supported download clients like qBittorrent. Prior to 2.9.10, TrustedNetworkAuthenticationHandler.ResolveClientIp parses the leftmost entry of the X-Forwarded-For header as the client IP. That entry…
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is attacker-controlled — X-Forwarded-For is append-only, so the leftmost value is whatever the original HTTP client claimed. By sending a spoofed local IP in the header, an unauthenticated remote attacker passes the trusted-network check and is logged in as the Cleanuparr administrator. This vulnerability is fixed in 2.9.10.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
X-Forwarded-For spoofing bypasses trusted-network auth on a public web app, directly enabling remote exploitation for initial access.
CVEs Like This One
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Directly counters DNS response spoofing by requiring cryptographic origin authentication before trusting resolved names/addresses.
Reveals spoofed logon attempts through unexpected previous logon timestamps upon legitimate login.
Training specifically addresses recognizing spoofed communications and phishing that enable authentication bypass.
Requiring verifiable identity evidence at appropriate assurance levels makes it substantially harder for attackers to successfully spoof or impersonate users to obtain accounts.
Unique device authentication makes successful spoofing of device identity substantially more difficult to achieve.
Unique identification of non-organizational users reduces the feasibility of authentication bypass by spoofing.
Unique identification and authentication of services before communications makes spoofing of service identities substantially harder.
Isolated trusted path ensures the user interacts only with genuine system components, preventing spoofing of authentication interfaces or prompts.
Hardening callouts derived
Configuration rules from DISA STIG baselines that reduce the attack surface for weaknesses of the type cited by this CVE. Derived transitively via CVE→CWE→STIG over `controls_xwalks` (authoritative rows only).
Oracle Linux 8 (3 rules)
- V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. via CWE-348
- V-248827 OL 8 must not have the rsh-server package installed. via CWE-290
- V-248827 OL 8 must not have the rsh-server package installed. via CWE-348
Oracle Linux 9 (1 rule)
- V-271525 OL 9 must have GPG signature verification enabled for all software repositories. via CWE-348
RHEL 7 (2 rules)
- V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. via CWE-290
- V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. via CWE-348
RHEL 8 (1 rule)
- V-230492 RHEL 8 must not have the rsh-server package installed. via CWE-290
Ubuntu 24.04 (1 rule)
- V-270708 Ubuntu 24.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. via CWE-348