CVE-2026-123568
Sveltejs devalue before 5.6.3 Prototype Pollution via uneval Output
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.
Fixes and workarounds
Fix
devalue (npm): OSV reports a fixed version 5.6.3. Check the advisory for supported release branches.
Source: OSV GHSA-8qm3-746x-r74rAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| devalue sveltejs devalue
npm |
≥ 0; < 5.6.3 (affected, semver) 5.6.3 (unaffected, semver) Other versions: unaffected |
CNA: VulnCheck |
devaluedevalue
npm |
≥ 0; < 5.6.3 (affected, semver); OSV events: introduced 0; fixed 5.6.3Source events (semver)Other versions: unaffected |
OSV GHSA-8qm3-746x-r74r |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 2.1 low |
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N | CNA: VulnCheck |
| 3.1 / 4.4 medium |
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N | CNA: VulnCheck |
| 4.0 / 2.1 low |
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/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: [email protected] |
| 3.1 / 4.4 medium |
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:L/I:L/A:N | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/sveltejs/devalue/security/advisories/GHSA-8qm3-746x-r74rCNA: VulnCheck · vendor-advisory
- https://www.vulncheck.com/advisories/sveltejs-devalue-before-5.6.3-prototype-pollution-via-uneval-outputCNA: VulnCheck · third-party-advisory
- https://github.com/sveltejs/devalue/security/advisories/GHSA-8qm3-746x-r74r[email protected]
- https://www.vulncheck.com/advisories/sveltejs-devalue-before-5.6.3-prototype-pollution-via-uneval-output[email protected]
- https://github.com/advisories/GHSA-8qm3-746x-r74rOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-8qm3-746x-r74rOSV / GitHub Security Advisories · osv
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