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

State: Published
Severity: 2.1 Low
Published: Oct 22, 2026
Updated: Oct 23, 2026
Reserved: Oct 22, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	2.1 Low	CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N	VulnCheck
3.1	2.6 Low	CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N	VulnCheck

Weaknesses

CWE-908 Use of Uninitialized Resource

Affected Products

Product	Versions
wasmtimebytecodealliance	before 36.0.17Affected 36.0.17Not affected 37.0.0 to before 48.0.4Affected 48.0.4Not affected 49.0.0 to before 49.0.2Affected 49.0.2Not affected

References

GitHub Security Advisory (GHSA-96f6-r43r-8c24)vendor-advisory
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_readdirthird-party-advisory

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