CVE-2026-123564
Sveltejs devalue before 5.9.3 Memory Exhaustion via uneval Sparse Arrays
Sveltejs devalue from 1.0.0 before 5.9.3 contains a memory exhaustion flaw in uneval, whose generated code for sparse arrays allocates memory proportional to the array's declared length when evaluated. Attackers who can influence a very large sparse array serialized by an application can exhaust memory in the browser or runtime evaluating the output.
Fixes and workarounds
Fix
devalue (npm): OSV reports a fixed version 5.9.3. Check the advisory for supported release branches.
Source: OSV GHSA-wf3x-273g-mvxvAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| devalue sveltejs devalue
npm |
≥ 1.0.0; < 5.9.3 (affected, semver) 5.9.3 (unaffected, semver) Other versions: unaffected |
CNA: VulnCheck |
devaluedevalue
npm |
≥ 1.0.0; < 5.9.3 (affected, semver); OSV events: introduced 1.0.0; fixed 5.9.3Source events (semver)Other versions: unaffected |
OSV GHSA-wf3x-273g-mvxv |
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-wf3x-273g-mvxvCNA: VulnCheck · vendor-advisory
- https://www.vulncheck.com/advisories/sveltejs-devalue-before-5.9.3-memory-exhaustion-via-uneval-sparse-arraysCNA: VulnCheck · third-party-advisory
- https://github.com/sveltejs/devalue/security/advisories/GHSA-wf3x-273g-mvxv[email protected]
- https://www.vulncheck.com/advisories/sveltejs-devalue-before-5.9.3-memory-exhaustion-via-uneval-sparse-arrays[email protected]
- https://github.com/advisories/GHSA-wf3x-273g-mvxvOSV / GitHub Security Advisories · advisory
- https://osv.dev/vulnerability/GHSA-wf3x-273g-mvxvOSV / GitHub Security Advisories · osv
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