# CVE-2026-86313: Samsung Walrus out-of-bounds write buffer overflow

Source: https://junglewise.ai/threats/cve-2026-86313-samsung-walrus-out-of-bounds-write-buffer-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-07. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-86313 · Severity: high · CVSS 7.8 · Published 2026-09-07

Samsung Walrus is an open-source WebAssembly runtime that can be embedded in applications to execute WebAssembly code safely. An out-of-bounds write vulnerability in Walrus allows an attacker to overflow buffers, potentially enabling arbitrary code execution or crashing the application. This could impact any software that relies on Walrus to isolate and execute untrusted WebAssembly code.

Technologies: [Samsung Walrus](https://junglewise.ai/threats/technologies/walrus). Vendors: [Samsung](https://junglewise.ai/threats/vendors/samsung).

## Quick answers

**Is CVE-2026-86313 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-86313 being exploited in the wild.

**How severe is CVE-2026-86313?** High severity, with a CVSS score of 7.8, published 7 September 2026.

**Which products and versions are affected?** Samsung Walrus commit af80e665ea49d9003695a66502f841ed1d8397e7 and prior.

**Is there a fix for CVE-2026-86313?** A patch was published on 2026-08-21: Fix merged in PR #482 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-86313 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-86313?** Check whether you run Samsung Walrus 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.

## Technical details

The vulnerability is a classic out-of-bounds write flaw in Samsung's Walrus WebAssembly runtime (commit af80e665ea49d9003695a66502f841ed1d8397e7). The vulnerability permits buffer overflow, allowing an attacker to write data beyond allocated memory boundaries. The attack vector is through crafted WebAssembly code that triggers the out-of-bounds write during runtime execution; no special authentication or elevated privileges are required beyond the ability to provide input to the runtime. A successful exploit could lead to memory corruption, denial of service, or potentially code execution depending on the specific memory layout and exploitability. A fix has been merged in Samsung's repository (PR #482), addressing the WASI compatibility issues and related test system updates.

## Affected products

- Samsung Walrus commit af80e665ea49d9003695a66502f841ed1d8397e7 and prior

## Timeline

- 2026-09-07: disclosed
- 2026-08-21: patched: Fix merged in PR #482

## References

- [https://github.com/Samsung/walrus/pull/482](https://github.com/Samsung/walrus/pull/482)

## Related threats

- [Samsung Walrus integer overflow in memory bounds check](https://junglewise.ai/threats/cve-2026-86314-samsung-walrus-integer-overflow-in-memory-bounds-check)
- [Samsung Walrus NULL pointer dereference](https://junglewise.ai/threats/cve-2026-47308-samsung-walrus-null-pointer-dereference)
- [Samsung Walrus NULL pointer dereference in WebAssembly engine](https://junglewise.ai/threats/cve-2026-47307-samsung-walrus-null-pointer-dereference-in-webassembly-engine)