CVE-2025-64345 | Wasmtime provides unsound API access to a WebAssembly shared linear memory

Wasmtime is a runtime for WebAssembly. Prior to version 38.0.4, 37.0.3, 36.0.3, and 24.0.5, Wasmtime's Rust embedder API contains an unsound interaction where a WebAssembly shared linear memory could be viewed as a type which provides safe access to the host (Rust) to the contents of the linear memory. This is not sound for shared linear memories, which could be modified in parallel, and this could lead to a data race in the host. Patch releases have been issued for all supported versions of Wasmtime, notably: 24.0.5, 36.0.3, 37.0.3, and 38.0.4. These releases reject creation of shared memories via `Memory::new` and shared memories are now excluded from core dumps. As a workaround, eembeddings affected by this issue should use `SharedMemory::new` instead of `Memory::new` to create shared memories. Affected embeddings should also disable core dumps if they are unable to upgrade. Note that core dumps are disabled by default but the wasm threads proposal (and shared memory) is enabled by default.

Published: 2025-11-12 Last update: 2026-04-15 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-64345 is rated Low Risk (7.5/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.01%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-64345

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-13 — 0.01% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-64345

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
1.8 3.1 LOW
CVSS:3.1/AV:L/AC:H/PR:H/UI:R/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 0.3 1.4 [email protected]

Weakness enumeration for CVE-2025-64345

GitHub Security Advisory for CVE-2025-64345

GHSA-hc7m-r6v8-hg9q · Severity: low · Ecosystem: rust — Wasmtime provides unsound API access to a WebAssembly shared linear memory

OS Trackers for CVE-2025-64345

vendor priority summary link
debian not yet assigned CVE-2025-64345 not yet assigned priority: Debian including 1 source packages (rust-wasmtime), 3 status rows across 3 suites (forky, sid, trixie): resolved 2, open 1. https://security-tracker.debian.org/tracker/CVE-2025-64345
redhat low — https://access.redhat.com/security/cve/CVE-2025-64345
ubuntu medium CVE-2025-64345 medium priority: Ubuntu including 1 source packages (rust-wasmtime), 5 status rows across 5 suites (jammy, noble, plucky, questing, upstream): needs-triage 3, DNE 1, ignored 1. https://ubuntu.com/security/CVE-2025-64345

Affected software / configurations for CVE-2025-64345

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-64345

cvelogic Threat Intelligence