CVE-2026-25150VulnerabilityPublished 3 Feb 2026

CVE-2026-25150: QwikDev qwik · Prototype Pollution

Affects QwikDev qwikSource CVE Database V5

Not known to be exploited · CVSS 9.3 Critical : upgrade to 1.19.0 as a priority.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

9.3Critical

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

EPSS: 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.19.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: None
Integrity: High
Availability: Low

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
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 impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Feb 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 2026-10-25.

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 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

Upgrade qwik and @builder.io/qwik to 1.19.0.

Affected software

Product	Affected	Fixed in
QwikDevqwik	Affected <1.19.0	Fixed in 1.19.0
npm@builder.io/qwik`pkg:npm/@builder.io/qwik`Other threats	Affected <1.19.0	Fixed in 1.19.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately upgrade all instances of the Qwik framework to version 1.19.0 or later, where the vulnerability has been patched. In cases where immediate upgrading is not feasible, implement input validation and sanitization at the application layer to reject or neutralize form field names containing dangerous prototype properties like __proto__, constructor, and prototype. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious HTTP POST requests attempting to exploit prototype pollution patterns. Conduct thorough code reviews and security testing focusing on object property handling and middleware components. Monitor application logs for unusual behavior indicative of prototype pollution attempts. Educate development teams about secure coding practices related to prototype pollution and JavaScript object handling. Finally, maintain an up-to-date inventory of all web applications using qwik to ensure comprehensive patch management and vulnerability tracking.

Description

CVE-2026-25150 is a critical prototype pollution vulnerability in the QwikDev qwik JavaScript framework versions prior to 1.19.0. The flaw exists in the formToObj() function of the @builder.io/qwik-city middleware, which improperly processes form field names containing dot notation without sanitizing dangerous property names like __proto__, constructor, and prototype. This allows unauthenticated attackers to send crafted HTTP POST requests that modify Object.prototype, potentially leading to privilege escalation, authentication bypass, or denial of service. The vulnerability has a CVSS score of 9.3, indicating critical severity, and affects all deployments using vulnerable qwik versions. Although no known exploits are currently in the wild, the ease of exploitation and impact on integrity make this a high-risk issue.

Impact

For European organizations, this vulnerability poses a serious risk to web applications built on the Qwik framework, especially those using versions prior to 1.19.0. Exploitation can lead to unauthorized privilege escalation, allowing attackers to gain higher access levels within applications, potentially compromising sensitive data and business logic. Authentication bypass could enable attackers to impersonate legitimate users, leading to data breaches or fraudulent activities. Denial of service conditions could disrupt critical services, impacting business continuity and customer trust. Given the widespread adoption of JavaScript frameworks in modern web development, organizations relying on qwik for performance-focused applications may face significant operational and reputational damage if exploited. Additionally, the vulnerability’s unauthenticated remote exploitability increases the likelihood of automated scanning and attacks, necessitating urgent remediation. Compliance with European data protection regulations such as GDPR may also be impacted if personal data is compromised due to this vulnerability.

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (opens in a new tab)
Variant weakness
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
Implementation
By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
Architecture and Design
By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
Implementation · Input Validation
When handling untrusted objects, validating using a schema can be used.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.2 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
Exploiting Incorrectly Configured Access Control Security Levels (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Feb 2026, 12:01 UTC

WeaknessesCWE-1321

Technical details

References

Community reviews

Related threats