Sveltejs devalue before 5.6.4 Prototype Injection via parse and unflatten
CVSS score
6.3
EPSS probability
—
Risk score
0.6
Published
8 h ago
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Vulnerability description
DayBreach AI Explanation
Verified against sourcesSources read
2
Source agreement
0/2
Evidence confidence
%34
Short explanation
Sveltejs devalue versions prior to 5.6.4 contain a prototype injection vulnerability in devalue.parse and devalue.unflatten that lets attackers inject __proto__ properties. When the results are merged via Object.assign, the target object's prototype can be altered. (S0, S1)
Prototype manipulation can enable unauthorized code execution or data leakage, affecting application security.
What should be done?
- Follow the vendor security advisory
- Upgrade to version 5.6.4 or later
- Validate input data securely
- Use a safe merging method instead of Object.assign
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Chain of evidence and sources
Sveltejs devalue 5.6.4 öncesi sürümler prototip enjeksiyonu içerir ve __proto__ özelliklerinin enjekte edilmesine izin verir (S0, S1).
Bu CVE için aktif istismar raporlanmamış; yama durumu resmi kaynaklarda doğrulanamamıştır (UNKNOWN) (S0).
Show the technical text from the sources
Sveltejs devalue before 5.6.4 contains a prototype injection vulnerability that allows attackers to inject __proto__ own properties into objects returned by devalue.parse and devalue.unflatten. Attackers can supply crafted serialized input that, when downstream code merges results via Object.assign, alters the target object's prototype.
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
CWE: CWE-1321
This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-123567 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | sveltejs | devalue | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 6.3 | CVSS V4_0 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | CVE CNA |
| 6.3 | CVSS V40 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD |
| 3.7 | CVSS V3_1 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N | CVE CNA |
| 3.7 | CVSS V31 | LOW | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-123567 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-123567 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
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