CVE-2026-123569
Devalue before 5.6.3 Denial of Service via Sparse Array Serialization
The devalue package for npm before 5.6.3 can consume excessive CPU and memory when serializing sparse arrays with uneval or stringify. An attacker who manages to get a sparse array created on the server, which mainstream wire formats do not allow, and serialized there can cause a denial of service.
Fixes and workarounds
Fix
devalue (npm): OSV reports a fixed version 5.6.3. Check the advisory for supported release branches.
Source: OSV GHSA-33hq-fvwr-56pmAffected 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-33hq-fvwr-56pm |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.7 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: VulnCheck |
| 4.0 / 8.7 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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: [email protected] |
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | 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-33hq-fvwr-56pmCNA: VulnCheck · vendor-advisory
- https://www.vulncheck.com/advisories/devalue-before-5.6.3-denial-of-service-via-sparse-array-serializationCNA: VulnCheck · third-party-advisory
- https://github.com/sveltejs/devalue/security/advisories/GHSA-33hq-fvwr-56pm[email protected]
- https://www.vulncheck.com/advisories/devalue-before-5.6.3-denial-of-service-via-sparse-array-serialization[email protected]
- https://github.com/advisories/GHSA-33hq-fvwr-56pmOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-33hq-fvwr-56pmOSV / GitHub Security Advisories · osv
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