What’s Vulnerable › Vulnerabilities

CVE-2026-115386: 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

• Severity: low (CVSS 2.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-22 · updated 2026-10-23
• Weakness: CWE-908

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.

Affected products

• bytecodealliance wasmtime: before 36.0.17; from 37.0.0 before 48.0.4; from 49.0.0 before 49.0.2 — fixed in 36.0.17, 48.0.4, 49.0.2

How to fix

Upgrade to a fixed version: bytecodealliance wasmtime 36.0.17, 48.0.4, 49.0.2. Check the vendor advisory for mitigations.

References

• https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-96f6-r43r-8c24
• 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

Get alerted when CVE-2026-115386 or the next vulnerability affects your stack