---
id: CVE-2026-115386
title: >-
  Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Memory
  Disclosure via fd_readdir
summary: >-
  Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2
  contains an information disclosure vulnerability in the WASIp1 fd_readdir
  implementation that copies uninitialized struct padding into guest memory.
  Guests with a pr…
severity: low
cvss: 2.6
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-908
vendor: bytecodealliance
product: wasmtime
affected:
  - wasmtime < 36.0.17
  - wasmtime >= 37.0.0 < 48.0.4
  - wasmtime >= 49.0.0 < 49.0.2
published: '2026-10-22'
updated: '2026-10-22'
sourceUpdated: '2026-10-22T19:13:52.931Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-115386'
references:
  - url: >-
      https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-96f6-r43r-8c24
    label: GitHub Security Advisory (GHSA-96f6-r43r-8c24)
  - url: >-
      https://www.vulncheck.com/advisories/wasmtime-before-36.0.17-37.0.0-before-48.0.4-and-49.0.0-before-49.0.2-memory-disclosure-via-fd-readdir
    label: >-
      VulnCheck Advisory: Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and
      49.0.0 before 49.0.2 Memory Disclosure via fd_readdir
tags:
  - cve.org
ingestedAt: '2026-10-22T22:00:50.405Z'
---

## Overview

Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an information disclosure vulnerability in the WASIp1 fd_readdir implementation that copies uninitialized struct padding into guest memory. Guests with a preopened directory can list entries to receive three bytes of leftover host stack or heap memory per directory entry.

## Affected

- `wasmtime < 36.0.17`
- `wasmtime >= 37.0.0 < 48.0.4`
- `wasmtime >= 49.0.0 < 49.0.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.