VulnerabilityPublished 20 Feb 2026

CVE-2026-26100: Owl opds · Incorrect Permissions

Affects Owl opdsSource CVE Database V5

Compare

Not known to be exploited · CVSS 6.8 Medium.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

6.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 0% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Local
Attack Complexity: Low
Attack Requirements: None
Privileges Required: Low
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: High
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: Low: The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the vulnerable system. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the vulnerable system.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Owlopds	Affected <=2.2.0.4	Fixed in–

AI-suggested

To mitigate CVE-2026-26100, organizations should immediately review and tighten permission settings on critical resources within Owl opds installations, ensuring that only necessary and trusted users have access. Network segmentation should be enforced to limit local access to the Owl opds service, especially restricting access to trusted hosts and users only. Implement strict access control policies and monitor local network traffic for unusual or unauthorized requests targeting the application. Since no patches are currently available, consider deploying host-based intrusion detection systems (HIDS) to detect anomalous file manipulations. Regularly audit file integrity using cryptographic hashes to identify unauthorized changes promptly. Additionally, restrict administrative privileges and enforce the principle of least privilege for all users interacting with the system. Prepare to apply vendor patches as soon as they are released and maintain up-to-date backups to enable recovery from potential file tampering. Finally, educate internal teams about the risks of local access exploitation and enforce strong internal security controls to prevent unauthorized lateral movement.

Description

Incorrect Permission Assignment for Critical Resource in Owl opds 2.2.0.4 allows File Manipulation via a crafted network request.

Impact

The primary impact of CVE-2026-26100 is on the integrity of affected systems running Owl opds 2.2.0.4. Unauthorized file manipulation can lead to data tampering, insertion of malicious code, or disruption of normal application behavior. Organizations relying on Owl opds for critical operations may face risks such as corrupted data, compromised application logic, or persistence of attacker-controlled files. Since the attack requires local access, environments with weak internal network segmentation or inadequate access controls are particularly vulnerable. The lack of authentication and user interaction requirements lowers the barrier for exploitation once local access is achieved. Although confidentiality and availability are not directly impacted, the integrity compromise can indirectly affect these areas if attackers leverage manipulated files for further attacks. The absence of known exploits currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time. Overall, organizations worldwide using Owl opds in environments where local access can be gained should consider this vulnerability a moderate risk to operational security and data integrity.

CWE-732Incorrect Permission Assignment for Critical Resource (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
Implementation
When using a critical resource such as a configuration file, check to see if the resource has insecure permissions (such as being modifiable by any regular user), and generate an error or even exit the software if there is a possibility that the resource could have been modified by an unauthorized party.
Architecture and Design
Divide the software into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully defining distinct user groups, privileges, and/or roles. Map these against data, functionality, and the related resources. Then set the permissions accordingly.
Architecture and Design · Operation · Sandbox or Jail
Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
OWASP Cheat Sheets
REST Assessment (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V4.3.3 (opens in a new tab)
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Directory Indexing (opens in a new tab)
Using Malicious Files (opens in a new tab)
Exploiting Incorrectly Configured Access Control Security Levels (opens in a new tab)
Signing Malicious Code (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

nozominetworks.com/labs/vulnerability-advisories-cve-2026-26100 (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Feb 2026, 14:08 UTC

WeaknessesCWE-732

Technical details

References

Community reviews

Related threats