CVE-2026-34983 | bytecodealliance wasmtime up to 43.0.0 API Call wasmtime::Linker use after free (GHSA-hfr4-7c6c-48w2)

VDB-356668 · CVE-2026-34983 · GHSA-HFR4-7C6C-48W2 BYTECODEALLIANCE WASMTIME UP TO 43.0.0 API CALL WASMTIME::LINKER USE AFTER FREE HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 3.5 $0-$5k 1.05 Summaryinfo A vulnerability was found in bytecodealliance wasmtime up to 43.0.0 and classified as critical. This issue affects the function wasmtime::Linker of the component API Call Handler. Executing a manipulation can lead to use after free. This vulnerability appears as CVE-2026-34983. The physical device can be targeted for the attack. There is no available exploit. It is suggested to upgrade the affected component. Detailsinfo A vulnerability was found in bytecodealliance wasmtime up to 43.0.0. It has been declared as problematic. This vulnerability affects the function wasmtime::Linker of the component API Call Handler. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes: Wasmtime is a runtime for WebAssembly. In 43.0.0, cloning a wasmtime::Linker is unsound and can result in use-after-free bugs. This bug is not controllable by guest Wasm programs. It can only be triggered by a specific sequence of embedder API calls made by the host. Specifically, the following steps must occur to trigger the bug clone a wasmtime::Linker, drop the original linker instance, use the new, cloned linker instance, resulting in a use-after-free. This vulnerability is fixed in 43.0.1. The advisory is shared for download at github.com. This vulnerability was named CVE-2026-34983 since 03/31/2026. The exploitation appears to be difficult. The attack needs to be approached locally. Additional levels of successful authentication are necessary for exploitation. There are known technical details, but no exploit is available. Upgrading to version 43.0.1 eliminates this vulnerability. Productinfo Vendor bytecodealliance Name wasmtime Version 43.0 Website Product: https://github.com/bytecodealliance/wasmtime/ CPE 2.3info 🔒 CPE 2.2info 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CNA CVSS-B Score: 🔒 CNA CVSS-BT Score: 🔒 CNA Vector: 🔒 CVSSv3info VulDB Meta Base Score: 3.6 VulDB Meta Temp Score: 3.5 VulDB Base Score: 3.6 VulDB Temp Score: 3.5 VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Use after free CWE: CWE-416 / CWE-119 CAPEC: 🔒 ATT&CK: 🔒 Physical: Yes Local: Yes Remote: Partially Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: wasmtime 43.0.1 Timelineinfo 03/31/2026 CVE reserved 04/09/2026 +9 days Advisory disclosed 04/09/2026 +0 days VulDB entry created 04/09/2026 +0 days VulDB entry last update Sourcesinfo Product: github.com Advisory: GHSA-hfr4-7c6c-48w2 Status: Confirmed CVE: CVE-2026-34983 (🔒) GCVE (CVE): GCVE-0-2026-34983 GCVE (VulDB): GCVE-100-356668 Entryinfo Created: 04/09/2026 22:04 Changes: 04/09/2026 22:04 (69) Complete: 🔍 Cache ID: 99:AB2:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸