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TI-2026-86710 Aliases CVE-2026-123568GHSA-7g65-3hpp-6gg5

Prototype pollution in Sveltejs devalue via uneval output

Priority LOW 26CWE-1321Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
None
Attack complexity
High
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Sveltejs devalue from 0 before 5.6.3 contains a prototype pollution flaw (CWE-1321) in uneval. Supplying untrusted data to uneval alters object prototypes, so the generated code creates objects with polluted prototypes when it is later evaluated. A remote attacker with high privileges can produce output whose shape differs from the original input.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

Description from the CNA

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.

Why it matters now

Fix Fixed devalue (sveltejs): 5.6.3

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
sveltejsdevaluebefore 5.6.35.6.3Patch availableCNA
  • devalue Vendorsveltejs Affected before 5.6.3 Fixed in 5.6.3 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:svelte:devalue:*:*:*:*:*:*:*:*——sveltejs
  • cpe:2.3:a:svelte:devalue:*:*:*:*:*:*:*:* Versions — — ·sveltejs

Remediation

Upgrade Sveltejs devalue to version 5.6.3, the fixed version.

Written with Claude Haiku 5.5 from the sources below · 2026-11-08

  • Fix · CNA devalue (sveltejs) Fixed in 5.6.3

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    sveltejs devalue 5.6.3

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-86711 Resource exhaustion in devalue npm package via sparse arraysPriority MEDIUM 53
    Show all 2 records →

Timeline

  1. 2026-11-08 Threatist record created from CVE-2026-123568
  2. 2026-11-08 Alias added: GHSA-7g65-3hpp-6gg5

References

Advisory 1

  • TI-2023-13469 SvelteKit framework has Insufficient CSRF protection for CORS requests CVSS 3.1HIGH 8.8
  • TI-2023-13464 SvelteKit has Insufficient Cross-Site Request Forgery Protection CVSS 3.1HIGH 8.8
  • TI-2024-15660 Sending a GET or HEAD request with a body crashes SvelteKit CVSS 3.1HIGH 7.5
  • TI-2024-30159 Potential mXSS vulnerability due to improper HTML escaping in svelte CVSS 3.1MEDIUM 6.1
  • TI-2025-23466 SvelteKit allows XSS via tracked search_params CVSS 3.1MEDIUM 5.4
  • TI-2025-13940 Svelte 5.46.0 - Hydratable Key Script-Breakout XSS (SSR) CVSS 4.0MEDIUM 5.3
See all 50 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences