CVE-2026-25150 — Qwik Prototype Pollution in qwik-city formToObj() Middleware
Qwik is a performance focused javascript framework. Prior to version 1.19.0, a prototype pollution vulnerability exists in the formToObj() function within @builder.io/qwik-city middleware. The function processes form field names with dot notation (e.g., user.name) to create nested objects, but fails to sanitize dangerous property names like __proto__, constructor, and prototype. This allows unauthenticated attackers to pollute Object.prototype by sending crafted HTTP POST requests, potentially leading to privilege escalation, authentication bypass, or denial of service. This issue has been patched in version 1.19.0.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.7% (30-day exploitation probability)+8
- Technical severity (critical)+10
- Automatable exploitation (SSVC)+3
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — github.com (NIST National Vulnerability Database)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Qwik Qwik, QwikDev Qwik).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (injection), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 10.0 | CVSS 3.1 | Critical | 3.9 | 6.0 | nvd@nist.gov via NIST National Vulnerability Database |
| 9.3 | CVSS 3.1 | Critical | 3.9 | 4.7 | security-advisories@github.com via NIST National Vulnerability Database |
| 9.3 | CVSS 3.1 | Critical | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.72%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Look for parameters with command/query metacharacters and unexpected child processes of the service.
Analysis and videos
CVE-2026-25150: Qwik Prototype Pollution in qwik-city formToObj() Middleware
CVE-2026-25150 is a prototype pollution flaw (CWE-1321) in the formToObj() function of the @builder.io/qwik-city middleware in Qwik versions before 1.19.0. The record states that unauthenticated attackers may reach it through crafted HTTP POST requests, with possible consequences including privilege escalation, authentication bypass or denial of service. The issue is patched in 1.19.0, and the record does not list it in CISA KEV.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · qwikdev/qwik
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 10.0
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
2 on the record
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-84994 Qwik: Crashing any Qwik Server via Resource thenable 2d
- High CVE-2026-32701 Qwik has array method pollution in FormData processing, allowing type confusion and DoS Mar 20, 2026
- Critical CVE-2026-27971 Qwik affected by unauthenticated RCE via server$ Deserialization Mar 3, 2026
- Medium CVE-2026-25148 Qwik SSR XSS via Unsafe Virtual Node Serialization Feb 3, 2026
- Medium CVE-2026-25149 Qwik City Open Redirect via fixTrailingSlash Feb 3, 2026
- Medium CVE-2026-25151 Qwik City has a CSRF Protection Bypass via Content-Type Header Validation Feb 3, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-25150 is "Qwik Prototype Pollution in qwik-city formToObj() Middleware", rated Critical. It affects Qwik (Qwik); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 10.0 describes technical severity. EPSS 0.72% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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