devalue has prototype pollution in devalue.parse and devalue.unflatten
Priority LOW 28CWE-1321Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
Summary
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In devalue v5.6.3 and earlier, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payloads. Successful exploitation could lead to Denial of Service (DoS) or type confusion. This vulnerability is fixed in 5.6.4.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00471 40th percentileScored 2026-11-07
Fix Fixed devalue (sveltejs): 5.6.4devalue (npm): 5.6.4
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| sveltejs | devalue | before 5.6.4 | 5.6.4 | Patch available | CNA |
| — | devalue (npm) | before 5.6.4 | 5.6.4 | Patch available | GHSA-cfw5-2vxh-hr84 |
- devalue Vendorsveltejs Affected before 5.6.4 Fixed in 5.6.4 Patch available CNA
- devalue (npm) Vendor— Affected before 5.6.4 Fixed in 5.6.4 Patch available GHSA-cfw5-2vxh-hr84
Remediation
- Fix · CNA devalue (sveltejs) Fixed in 5.6.4
- Fix · GHSA-cfw5-2vxh-hr84 devalue (npm) Fixed in 5.6.4 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 2 products
- Red Hat Build of Podman Desktop - Tech Preview
- Red Hat Trusted Artifact Signer
Timeline
- 2026-10-02 Threatist record created from CVE-2026-30226
- 2026-10-03 Alias added: GHSA-cfw5-2vxh-hr84
References
More sveltejs Devalue vulnerabilities
- TI-2026-18293 devalue vulnerable to denial of service due to memory/CPU exhaustion in devalue.parse CVSS 3.1HIGH 7.5
- TI-2026-18292 devalue vulnerable to denial of service due to memory exhaustion in devalue.parse CVSS 3.1HIGH 7.5
- TI-2026-30850 Svelte devalue: DoS via sparse array deserialization CVSS 3.1HIGH 7.5
Sources
- CVE-2026-30226 · CVE Program
- CVE-2026-30226 · NVD
- FIRST EPSS
- GHSA-cfw5-2vxh-hr84 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-30226 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences