CVE-2022-39393 | Wasmtime vulnerable to data leakage between instances in the pooling allocator

Wasmtime is a standalone runtime for WebAssembly. Prior to versions 2.0.2 and 1.0.2, there is a bug in Wasmtime's implementation of its pooling instance allocator where when a linear memory is reused for another instance the initial heap snapshot of the prior instance can be visible, erroneously to the next instance. This bug has been patched and users should upgrade to Wasmtime 2.0.2 and 1.0.2. Other mitigations include disabling the pooling allocator and disabling the `memory-init-cow`.

Published: 2022-11-10 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2022-39393 is rated Moderate Risk (50.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.66%). Review affected assets and schedule remediation.

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-2022-39393

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 2026-06-15 0.59% 0.66% +0.06%
2 2026-06-10 0.32% 0.59% +0.27%
3 2025-11-18 — 0.32% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2022-39393

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 4.0 [email protected]
8.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 4.0 [email protected]

Weakness enumeration for CVE-2022-39393

GitHub Security Advisory for CVE-2022-39393

GHSA-wh6w-3828-g9qf · Severity: high · Ecosystem: rust — Wasmtime may have data leakage between instances in the pooling allocator

OS Trackers for CVE-2022-39393

vendor priority summary link
debian unimportant CVE-2022-39393 unimportant priority: Debian including 1 source packages (rust-wasmtime), 3 status rows across 3 suites (forky, sid, trixie): resolved 3. https://security-tracker.debian.org/tracker/CVE-2022-39393
ubuntu medium CVE-2022-39393 medium priority: Ubuntu including 7 source packages (firefox, mozjs38, …), 58 status rows across 10 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 27, ignored 24, not-affected 5, needs-triage 2. https://ubuntu.com/security/CVE-2022-39393

Affected software / configurations for CVE-2022-39393

Vendor Product Version Raw CPE
bytecodealliance wasmtime < 1.0.2 cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*
bytecodealliance wasmtime >= 2.0.0, < 2.0.2 cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*

References for CVE-2022-39393

cvelogic Threat Intelligence