CVE-2026-34941 | bytecodealliance wasmtime up to 24.0.6/36.0.6/42.0.1/44.0.0 out-of-bounds (GHSA-hx6p-xpx3-jvvv)

VDB-356649 · CVE-2026-34941 · GHSA-HX6P-XPX3-JVVV BYTECODEALLIANCE WASMTIME UP TO 24.0.6/36.0.6/42.0.1/44.0.0 OUT-OF-BOUNDS HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 6.2 $0-$5k 0.47+ Summaryinfo A vulnerability classified as problematic has been found in bytecodealliance wasmtime up to 24.0.6/36.0.6/42.0.1/44.0.0. The impacted element is an unknown function. Performing a manipulation results in out-of-bounds. This vulnerability is cataloged as CVE-2026-34941. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component. Detailsinfo A vulnerability was found in bytecodealliance wasmtime up to 24.0.6/36.0.6/42.0.1/44.0.0. It has been classified as critical. This affects some unknown processing. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on availability. The summary by CVE is: Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a vulnerability where when transcoding a UTF-16 string to the latin1+utf16 component-model encoding it would incorrectly validate the byte length of the input string when performing a bounds check. Specifically the number of code units were checked instead of the byte length, which is twice the size of the code units. This vulnerability can cause the host to read beyond the end of a WebAssembly's linear memory in an attempt to transcode nonexistent bytes. In Wasmtime's default configuration this will read unmapped memory on a guard page, terminating the process with a segfault. Wasmtime can be configured, however, without guard pages which would mean that host memory beyond the end of linear memory may be read and interpreted as UTF-16. A host segfault is a denial-of-service vulnerability in Wasmtime, and possibly being able to read beyond the end of linear memory is additionally a vulnerability. Note that reading beyond the end of linear memory requires nonstandard configuration of Wasmtime, specifically with guard pages disabled. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1. The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-34941 since 03/31/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Neither technical details nor an exploit are publicly available. Upgrading to version 24.0.7, 36.0.7, 42.0.2 or 44.0.1 eliminates this vulnerability. Productinfo Vendor bytecodealliance Name wasmtime Version 24.0.0 24.0.1 24.0.2 24.0.3 24.0.4 24.0.5 24.0.6 36.0.0 36.0.1 36.0.2 36.0.3 36.0.4 36.0.5 36.0.6 42.0.0 42.0.1 44.0 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: 6.5 VulDB Meta Temp Score: 6.2 VulDB Base Score: 6.5 VulDB Temp Score: 6.2 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: Out-of-bounds CWE: CWE-125 / CWE-119 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Yes 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 24.0.7/36.0.7/42.0.2/44.0.1 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-hx6p-xpx3-jvvv Status: Confirmed CVE: CVE-2026-34941 (🔒) GCVE (CVE): GCVE-0-2026-34941 GCVE (VulDB): GCVE-100-356649 Entryinfo Created: 04/09/2026 21:36 Changes: 04/09/2026 21:36 (67) Complete: 🔍 Cache ID: 99:6FA:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸