# Bytecode Alliance Wasmtime-Wasi vulnerabilities

Source: https://junglewise.ai/threats/technologies/bytecode-alliance-wasmtime-wasi  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Updated: 9 November 2026, 03:07 UTC. Rebuilt every hour.  
Data: https://junglewise.ai/threats/technologies/bytecode-alliance-wasmtime-wasi.json  
License: CC BY 4.0 with a link back

Junglewise Threat Intelligence has tracked 5 vulnerabilities in Bytecode Alliance Wasmtime-Wasi: 0 in the last 7 days and 3 in the last 90 days, 0 of them critical and 0 exploited in the wild. The most recent, Wasmtime-WASI filesystem sandbox escape with symlink rename, was published on 14 October 2026. 1 vulnerability in the last four weeks, down 50% on the four before (2).

## Counts

- Last 7 days: 0
- Last 30 days: 1
- Last 90 days: 3
- All time: 5 (0 critical, 0 exploited in the wild)

## About Bytecode Alliance Wasmtime-Wasi

WebAssembly runtime component providing WASI (WebAssembly System Interface) functionality for wasmtime.

## Latest Bytecode Alliance Wasmtime-Wasi vulnerabilities

- [Wasmtime-WASI filesystem sandbox escape with symlink rename](https://junglewise.ai/threats/rustsec-2026-0352-filesystem-sandbox-escape-when-renaming-symlinks-with-86b22c86) (medium, CVSS 4, published 14 Oct 2026)
- [wasmtime-wasi excessive memory allocation when guests lack stdio](https://junglewise.ai/threats/rustsec-2026-0322-excessive-allocated-memory-on-the-host-when-guests-84ef0787) (medium, CVSS 4, published 2 Oct 2026)
- [Wasmtime wasmtime-wasi fd_readdir information disclosure](https://junglewise.ai/threats/rustsec-2026-0323-fd-readdir-copies-uninitialized-struct-padding-into-ed3c3a69) (medium, CVSS 4, published 2 Oct 2026)
- [CVE-2026-54786: Bytecode Alliance Wasmtime resource leak in WASIp1 fd_renumber](https://junglewise.ai/threats/cve-2026-54786-bytecode-alliance-wasmtime-resource-leak-in-wasip1-fd-renumber) (medium, CVSS 5, published 1 Jul 2026)
- [CVE-2026-47261: Bytecode Alliance Wasmtime access control bypass in wasmtime-wasi](https://junglewise.ai/threats/cve-2026-47261-bytecode-alliance-wasmtime-access-control-bypass-in-wasmtime-wasi) (high, CVSS 7.5, published 15 Jun 2026)

## Most severe Bytecode Alliance Wasmtime-Wasi vulnerabilities

- [CVE-2026-47261: Bytecode Alliance Wasmtime access control bypass in wasmtime-wasi](https://junglewise.ai/threats/cve-2026-47261-bytecode-alliance-wasmtime-access-control-bypass-in-wasmtime-wasi) (high, CVSS 7.5, published 15 Jun 2026)
- [CVE-2026-54786: Bytecode Alliance Wasmtime resource leak in WASIp1 fd_renumber](https://junglewise.ai/threats/cve-2026-54786-bytecode-alliance-wasmtime-resource-leak-in-wasip1-fd-renumber) (medium, CVSS 5, published 1 Jul 2026)
- [Wasmtime-WASI filesystem sandbox escape with symlink rename](https://junglewise.ai/threats/rustsec-2026-0352-filesystem-sandbox-escape-when-renaming-symlinks-with-86b22c86) (medium, CVSS 4, published 14 Oct 2026)
- [wasmtime-wasi excessive memory allocation when guests lack stdio](https://junglewise.ai/threats/rustsec-2026-0322-excessive-allocated-memory-on-the-host-when-guests-84ef0787) (medium, CVSS 4, published 2 Oct 2026)
- [Wasmtime wasmtime-wasi fd_readdir information disclosure](https://junglewise.ai/threats/rustsec-2026-0323-fd-readdir-copies-uninitialized-struct-padding-into-ed3c3a69) (medium, CVSS 4, published 2 Oct 2026)

## Vulnerabilities per week

1 vulnerability in the last four weeks, down 50% on the four before (2).

| Week of | Vulns | Critical | Exploited |
| --- | --- | --- | --- |
| 17 Aug 2026 | 0 | 0 | 0 |
| 24 Aug 2026 | 0 | 0 | 0 |
| 31 Aug 2026 | 0 | 0 | 0 |
| 7 Sep 2026 | 0 | 0 | 0 |
| 14 Sep 2026 | 0 | 0 | 0 |
| 21 Sep 2026 | 0 | 0 | 0 |
| 28 Sep 2026 | 2 | 0 | 0 |
| 5 Oct 2026 | 0 | 0 | 0 |
| 12 Oct 2026 | 1 | 0 | 0 |
| 19 Oct 2026 | 0 | 0 | 0 |
| 26 Oct 2026 | 0 | 0 | 0 |
| 2 Nov 2026 | 0 | 0 | 0 |
| 9 Nov 2026 | 0 | 0 | 0 |

## Other Bytecode Alliance technologies

- [Bytecode Alliance Wasmtime](https://junglewise.ai/threats/technologies/bytecode-alliance-wasmtime): 55 vulnerabilities

## Sources

NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "Bytecode Alliance Wasmtime-Wasi vulnerabilities", https://junglewise.ai/threats/technologies/bytecode-alliance-wasmtime-wasi, 9 November 2026.