CVE-2026-115386 Details
Description
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.
A memory disclosure vulnerability has been identified in Wasmtime versions prior to 36.0.17, between 37.0.0 and 48.0.4, and between 49.0.0 and 49.0.2. The issue arises in the WASIp1 implementation of the fd_readdir function, where uninitialized struct padding is inadvertently copied into guest memory. This vulnerability allows guests with a preopened directory to list entries and receive three bytes of residual host stack or heap memory for each directory entry.
Users are advised to upgrade to Wasmtime versions 36.0.17, 48.0.4, or 49.0.2. There is no workaround available for this issue if WASIp1 is enabled and guests have access to a preopened directory.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 22, 2026CISA-ADP
Assessed Oct 23, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-908 | Use of Uninitialized Resource | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| bytecodealliance Wasmtime | < 36.0.17 (semver) >= 37.0.0 (semver) < 48.0.4 (semver) >= 49.0.0 (semver) < 49.0.2 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 23, 2026 | CVE Modified | CISA-ADP |
| Oct 22, 2026 | New CVE Received | [email protected] |