# CVE-2026-92708: Svelte devalue memory disclosure in Node Buffer serialization

Source: https://junglewise.ai/threats/cve-2026-92708-svelte-devalue-is-a-javascript-library-that-serializes-values  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-92708 · Severity: high · CVSS 7.5 · Published 2026-09-18

Svelte devalue is a JavaScript library used in server-side rendering frameworks like SvelteKit to serialize application data into HTML. When serializing Node Buffer objects, versions 5.1.0 through 5.9.2 leak up to 64 KB of unrelated process memory, including other users' request bodies and authentication headers. This occurs automatically during page rendering without requiring authentication, allowing attackers to extract sensitive information from concurrent requests.

Technologies: [devalue (npm)](https://junglewise.ai/threats/technologies/devalue), [Svelte Devalue](https://junglewise.ai/threats/technologies/svelte-devalue). Vendors: [npm](https://junglewise.ai/threats/vendors/npm), [Svelte](https://junglewise.ai/threats/vendors/svelte).

## Quick answers

**Is CVE-2026-92708 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-92708 being exploited in the wild.

**How severe is CVE-2026-92708?** High severity, with a CVSS score of 7.5, published 18 September 2026.

**Which products and versions are affected?** devalue (npm) >= 5.1.0, <= 5.9.2, SEMVER:introduced=5.1.0,fixed=5.9.3; Svelte Devalue 5.1.0 through 5.9.2.

**Is there a fix for CVE-2026-92708?** Yes. devalue (npm): upgrade to 5.9.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-92708 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-92708?** Check whether you run devalue (npm) or Svelte Devalue at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- devalue (npm): upgrade to 5.9.3 or later

  ```sh
  npm install devalue@5.9.3
  ```


## Technical details

The stringify, stringifyAsync, and uneval functions serialize typed arrays by emitting their entire backing ArrayBuffer rather than only the visible view. Node Buffers share a process-wide allocation pool, so serializing a small Buffer discloses adjacent unrelated memory. The vulnerability fires on every server-side render and bypasses the library's parse/unflatten guards since serialization occurs before parsing. Fixed in version 5.9.3 by serializing only visible Buffer bytes.

## Affected products

- Svelte devalue 5.1.0 through 5.9.2

## Identifiers

- CVE-2026-92708
- GHSA-j22f-vq7h-c4qm

## Timeline

- 2026-09-18: disclosed
- 2026-09-18: patched: version 5.9.3

## References

- [https://github.com/sveltejs/devalue/commit/46dc877b3570dafb1cd3291b9bb48cecef8f7266](https://github.com/sveltejs/devalue/commit/46dc877b3570dafb1cd3291b9bb48cecef8f7266)
- [https://github.com/sveltejs/devalue/releases/tag/v5.9.3](https://github.com/sveltejs/devalue/releases/tag/v5.9.3)

## Related threats

- [Devalue validation bypass in ArrayBuffer reviver](https://junglewise.ai/threats/cve-2026-123563-devalue-before-5-9-3-contains-a-validation-bypass-vulnerability)
- [devalue uneval sparse-array CPU amplification](https://junglewise.ai/threats/devalue-residual-sparse-array-cpu-amplification-in-uneval-288a909c)
- [devalue quadratic expansion in uneval with repeated primitives](https://junglewise.ai/threats/devalue-repeated-primitive-strings-cause-quadratic-expansion-in-uneval-9363872e)
- [devalue sparse arrays excessive memory allocation in uneval](https://junglewise.ai/threats/devalue-sparse-arrays-emitted-by-uneval-cause-eager-allocation-when-79528840)
- [devalue ArrayBuffer allocation bypass via custom reviver](https://junglewise.ai/threats/devalue-custom-arraybuffer-revivers-can-bypass-typed-array-allocation-ecd9322f)