CVE-2026-28201: Open Notebook · Improper Input Validation
Affects Open NotebookSource GCVE Database
Not known to be exploited · CVSS 8.7 High.
Data as of 27 Oct 2026, 00:07 UTC
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N- Attack Vector
- Network
- Attack Complexity
- Low
- Attack Requirements
- None
- Privileges Required
- None
- User Interaction
- Passive
- Vulnerable system confidentiality
- High
- Vulnerable system integrity
- High
- Vulnerable system availability
- High
- 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: Network
- The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
- 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: None
- The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
- User Interaction: Passive
- Successful exploitation of this vulnerability requires limited interaction by the targeted user with the vulnerable system and the attacker’s payload. These interactions would be considered involuntary and do not require that the user actively subvert protections built into the vulnerable system.
- Vulnerable system confidentiality: High
- There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
- 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: High
- There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the Vulnerable System; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the Vulnerable System (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).
- 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 7 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
- Weaponised
- Public exploit code exists in Metasploit or Exploit-DB, 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 |
|---|---|---|
| Open Notebook Open Notebook | Affected
| Fixed in– |
Description
An improper input validation, together with an overly permissive default CORS configuration in Open Notebook v1.8.1 allows remote attacker to trick a legitimate user to alter or delete arbitrary database entries via specially crafted malicious URL. Depending on the deployment, data exfiltration is also possible.
- CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-917Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection') (opens in a new tab)
Base weaknessOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.
Architecture and Design
Avoid adding user-controlled data into an expression interpreter when possible.
Implementation
If user-controlled data must be added to an expression interpreter, one or more of the following should be performed: Validate that the user input will not evaluate as an expression; Encode the user input in a way that ensures it is not evaluated as an expression
System Configuration · Operation
The framework or tooling might allow the developer to disable or deactivate the processing of EL expressions, such as setting the isELIgnored attribute for a JSP page to "true".
- OWASP Cheat Sheets
- OWASP ASVS 4.0.3
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- CWE-352Cross-Site Request Forgery (CSRF) (opens in a new tab)
Compound weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #3OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation
Ensure that the application is free of cross-site scripting issues (CWE-79), because most CSRF defenses can be bypassed using attacker-controlled script.
Architecture and Design
Generate a unique nonce for each form, place the nonce into the form, and verify the nonce upon receipt of the form. Be sure that the nonce is not predictable (CWE-330).
- OWASP Cheat Sheets
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
- Assigned by (CNA)
- EU Agency for Cybersecurity (ENISA) (opens in a new tab) · Consortium · Greece
- Reserved
- CVSS version
- 4.0
- GCVE source
- db.gcve.eu
References
Community reviews
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