CVE-2026-73647 — Quasar Framework: Prototype pollution in Quasar extend() utility
Quasar Framework is a framework for building high-performance Vue.js user interfaces. Prior to 2.22.0, the public extend() utility in ui/src/utils/extend/extend.js recursively copied attacker-controlled object keys during extend(true, target, source) deep merges without rejecting an own __proto__ property. The merge could descend into the prototype object and write attacker-controlled properties to Object.prototype in the same JavaScript process. Applications that passed user-controlled or partially user-controlled objects to extend() could experience logic bypass, unsafe default-option injection, denial of service, or other application-specific impact when polluted properties were later consumed. This issue is fixed in version 2.22.0.
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
- Technical severity (medium)+3
- CISA SSVC: exploitation "poc"+5
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.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
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 (Quasarframework Quasar).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- 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.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Quasarframework | Quasar | version < 2.22.0 | Vulnerable | CVE Program (cve.org) e CISA ADP |
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 |
|---|---|---|---|---|---|
| 5.6 | CVSS 3.1 | Medium | 2.2 | 3.4 | security-advisories@github.com via NIST National Vulnerability Database |
| 5.6 | CVSS 3.1 | Medium | — | — | GitHub_M via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L (score shown at the top: security-advisories@github.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
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.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · quasarframework/quasar
- SSVC assessment updated
- Record published
- CVSS changed · 5.6
- Source status changed · → Deferred
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
3 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-106108 Quasar Framework: App Vite SSG page output paths can escape the configured distribution directory 2d
- High CVE-2026-106107 Quasar Framework: App Vite SSR and SSG nonce attributes are not safely constrained 9d
- Medium CVE-2026-106109 Quasar Framework: App Vite build cleanup can recursively remove unsafe configured output directories 9d
- High CVE-2026-106106 Quasar Framework: SSR/SSG dev error page discloses the full shell environment and its </script> escape is bypassable 9d
- High CVE-2026-106103 Quasar Framework: Path Traversal / Arbitrary File Write via crafted Icon Genie profile 9d
- High CVE-2026-106105 Quasar Framework: Development TLS private keys are cached with overly permissive filesystem permissions 9d
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 FIRST EPSS score.
- No fixed version, patch or mitigation documented.
- 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-2026-73647 is "Quasar Framework: Prototype pollution in Quasar extend() utility", rated Medium. It affects Quasar (Quasarframework); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.6 describes technical severity. 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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