{"answers":{"affected":"7 open source packages ship an affected version, including wasmtime. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-34945 in the wild and no public exploit code.","fix":"Upgrade wasmtime to a fixed version for your release line: 36.0.7, 42.0.2 or 43.0.1.","what":"CVE-2026-34945 is a low-severity vulnerability in bytecodealliance wasmtime, published on 9 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-34945 and fix it if it is affected.\n\nWhat it is: CVE-2026-34945 is a low-severity vulnerability in bytecodealliance wasmtime, published on 9 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-34945 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- wasmtime (crates.io): affected from 0.0.0-0; fixed in 36.0.7, 42.0.2, 43.0.1\n- wasmtime (crates.io): affected from 25.0.0; fixed in 36.0.7\n- wasmtime (crates.io): affected from 25.0.0; fixed in 36.0.7\n- wasmtime (crates.io): affected from 37.0.0; fixed in 42.0.2\n- wasmtime (crates.io): affected from 37.0.0; fixed in 42.0.2\n- wasmtime (crates.io): affected from 43.0.0; fixed in 43.0.1\n- wasmtime (crates.io): affected from 43.0.0; fixed in 43.0.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-34945/ (Markdown: https://insights.sbomify.com/CVE-2026-34945/index.md)","id":"CVE-2026-34945","markdown":"https://insights.sbomify.com/CVE-2026-34945/index.md","name":"CVE-2026-34945","record":{"aliases":["DEBIAN-CVE-2026-34945","GHSA-m9w2-8782-2946","JLSEC-2026-1358","RUSTSEC-2026-0086","UBUNTU-CVE-2026-34945","openSUSE-SU-2026:10598-1"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["data_read"],"network_reachable":"yes","non_default_config":true,"product_category":"WebAssembly runtime","requires_auth":"low_privilege","summary":"A bug in Wasmtime's Winch compiler allows WebAssembly guests to read sensitive host stack data when using 64-bit tables.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"wasmtime","vendor":"bytecodealliance"}],"cvss":{"score":2.3,"severity":"low","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-681","name":"Incorrect Conversion between Numeric Types"}],"description":"Wasmtime is a runtime for WebAssembly. From 25.0.0 to before 36.0.7, 42.0.2, and 43.0.1, Wasmtime's Winch compiler contains a bug where a 64-bit table, part of the memory64 proposal of WebAssembly, incorrectly translated the table.size instruction. This bug could lead to disclosing data on the host's stack to WebAssembly guests. The host's stack can possibly contain sensitive data related to other host-originating operations which is not intended to be disclosed to guests. This bug specifically arose from a mistake where the return value of table.size was statically typed as a 32-bit integer, as opposed to consulting the table's index type to see how large the returned register could be. When combined with details about Wnich's ABI, such as multi-value returns, this can be combined to read stack data from the host, within a guest. This vulnerability is fixed in 36.0.7, 42.0.2, and 43.0.1.","ecosystems":["crates.io","openSUSE:Tumbleweed"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Wasmtime leaks host data with 64-bit tables and Winch","id":"CVE-2026-34945","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"crates.io","product":null,"products":[],"type":"information_disclosure","year":"2026"},"n_packages":8,"n_references":1,"next":{"headline":"Wasmtime's host panics when Winch compiler executes `table.fill`","id":"CVE-2026-34946"},"packages":[{"ecosystem":"crates.io","fixed":["36.0.7","42.0.2","43.0.1"],"introduced":["0.0.0-0","37.0.0","43.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"RUSTSEC-2026-0086"},{"ecosystem":"crates.io","fixed":["36.0.7"],"introduced":["25.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-m9w2-8782-2946"},{"ecosystem":"crates.io","fixed":["36.0.7"],"introduced":["25.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-m9w2-8782-2946"},{"ecosystem":"crates.io","fixed":["42.0.2"],"introduced":["37.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-m9w2-8782-2946"},{"ecosystem":"crates.io","fixed":["42.0.2"],"introduced":["37.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-m9w2-8782-2946"},{"ecosystem":"crates.io","fixed":["43.0.1"],"introduced":["43.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-m9w2-8782-2946"},{"ecosystem":"crates.io","fixed":["43.0.1"],"introduced":["43.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-m9w2-8782-2946"},{"ecosystem":"openSUSE:Tumbleweed","fixed":["0.26.8-1.1"],"introduced":["0"],"last_affected":[],"package":"tree-sitter","purl":"pkg:rpm/opensuse/tree-sitter\u0026distro=openSUSE%20Tumbleweed","source":"openSUSE-SU-2026:10598-1"}],"prev":{"headline":"Wasmtime segfault or unused out-of-sandbox load with `f64x2.splat` operator on x86-64","id":"CVE-2026-34944"},"products":["wasmtime"],"published":"2026-04-09","related":[{"cvss_score":9,"headline":"Wasmtime miscompiled guest heap access enables sandbox escape on aarch64 Cranelift","id":"CVE-2026-34971","kev_date_added":null,"published":"2026-04-09"},{"cvss_score":9,"headline":"Wasmtime with Winch compiler backend on aarch64 may allow a sandbox-escaping memory access","id":"CVE-2026-34987","kev_date_added":null,"published":"2026-04-09"},{"cvss_score":8.6,"headline":"Wasmtime vulnerable to data leakage between instances in the pooling allocator","id":"CVE-2022-39393","kev_date_added":null,"published":"2022-11-10"},{"cvss_score":8.1,"headline":"Use after free in Wasmtime","id":"CVE-2022-24791","kev_date_added":null,"published":"2022-03-31"},{"cvss_score":7.5,"headline":"Wasmtime: WASI path_open(TRUNCATE) bypasses `FilePerms::WRITE` host restriction","id":"CVE-2026-47261","kev_date_added":null,"published":"2026-06-15"},{"cvss_score":6.9,"headline":"Wasmtime has a Heap OOB read in component model UTF-16 to latin1+utf16 string transcoding","id":"CVE-2026-34941","kev_date_added":null,"published":"2026-04-09"},{"cvss_score":6.9,"headline":"Wasmtime is vulnerable to panic when dropping a `[Typed]Func::call_async` future","id":"CVE-2026-27195","kev_date_added":null,"published":"2026-02-24"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"open","licence":"CC0 1.0","name":"RustSec","prefix":"RUSTSEC"},{"class":"attribution","licence":"CC BY 4.0","name":"SUSE","prefix":"openSUSE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-04-10","vendors":["bytecodealliance"]},"summary":"A bug in Wasmtime's Winch compiler allows WebAssembly guests to read sensitive host stack data when using 64-bit tables.","url":"https://insights.sbomify.com/CVE-2026-34945/"}