CVSS 4.0
2.1 lowCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:NCVE-2026-123568
Low (2.1) in sveltejs devalue. EPSS 0.2% estimated probability of exploitation activity in the next 30 days. Fixed in devalue 5.6.3.
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Sveltejs devalue before 5.6.3 contains a prototype pollution vulnerability that allows attackers to alter object prototypes by supplying untrusted data to uneval. When the generated code is later evaluated, it creates objects with polluted prototypes, producing output data whose shape differs from the original input.
Severity
CVSS 3.1
4.4 mediumCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 10th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)
- Published
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Explain CVE-2026-123568 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123568?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123568?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123568 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| sveltejs devalue | before 5.6.3 |
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-8qm3-746x-r74r | npm | devalue | <5.6.3 | 5.6.3 |
Attack patterns (CAPEC)
- CAPEC-1 Accessing Functionality Not Properly Constrained by ACLs Likelihood: High · Severity: High
- CAPEC-77 Manipulating User-Controlled Variables Likelihood: High · Severity: Very High
- CAPEC-180 Exploiting Incorrectly Configured Access Control Security Levels Likelihood: High · Severity: Medium
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.