{"answers":{"affected":"9 open source packages ship an affected version, including wasmtime. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-34943 in the wild and no public exploit code.","fix":"Upgrade wasmtime to a fixed version for your release line: 24.0.7, 36.0.7, 42.0.2 or 43.0.1.","what":"CVE-2026-34943 is a medium-severity denial of service vulnerability in bytecodealliance wasmtime, published on 9 Apr 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-34943 and fix it if it is affected.\n\nWhat it is: CVE-2026-34943 is a medium-severity denial of service vulnerability in bytecodealliance wasmtime, published on 9 Apr 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.\nExploitation: There is no known exploitation of CVE-2026-34943 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- wasmtime (crates.io): affected all versions; fixed in 24.0.7\n- wasmtime (crates.io): affected all versions; fixed in 24.0.7\n- wasmtime (crates.io): affected from 0.0.0-0; fixed in 24.0.7, 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-2026-34943/ (Markdown: https://insights.sbomify.com/CVE-2026-34943/index.md)","id":"CVE-2026-34943","markdown":"https://insights.sbomify.com/CVE-2026-34943/index.md","name":"CVE-2026-34943","record":{"aliases":["DEBIAN-CVE-2026-34943","GHSA-m758-wjhj-p3jq","JLSEC-2026-1356","RUSTSEC-2026-0085","UBUNTU-CVE-2026-34943"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"WebAssembly runtime","requires_auth":"high_privilege","summary":"A guest-controlled panic in Wasmtime when lifting flags values allows attackers to cause a denial of service against the host runtime.","user_interaction":"required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"wasmtime","vendor":"bytecodealliance"}],"cvss":{"score":5.6,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-248","name":"Uncaught Exception"}],"description":"Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime contains a possible panic which can happen when a flags-typed component model value is lifted with the Val type. If bits are set outside of the set of flags the component model specifies that these bits should be ignored but Wasmtime will panic when this value is lifted. This panic only affects wasmtime's implementation of lifting into Val, not when using the flags! macro. This additionally only affects flags-typed values which are part of a WIT interface. This has the risk of being a guest-controlled panic within the host which Wasmtime considers a DoS vector. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.","ecosystems":["crates.io"],"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 panics when lifting `flags` component value","id":"CVE-2026-34943","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"crates.io","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":9,"n_references":1,"next":{"headline":"Wasmtime segfault or unused out-of-sandbox load with `f64x2.splat` operator on x86-64","id":"CVE-2026-34944"},"packages":[{"ecosystem":"crates.io","fixed":["24.0.7"],"introduced":["0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-m758-wjhj-p3jq"},{"ecosystem":"crates.io","fixed":["24.0.7"],"introduced":["0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-m758-wjhj-p3jq"},{"ecosystem":"crates.io","fixed":["24.0.7","36.0.7","42.0.2","43.0.1"],"introduced":["0.0.0-0","25.0.0","37.0.0","43.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"RUSTSEC-2026-0085"},{"ecosystem":"crates.io","fixed":["36.0.7"],"introduced":["25.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-m758-wjhj-p3jq"},{"ecosystem":"crates.io","fixed":["36.0.7"],"introduced":["25.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-m758-wjhj-p3jq"},{"ecosystem":"crates.io","fixed":["42.0.2"],"introduced":["37.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-m758-wjhj-p3jq"},{"ecosystem":"crates.io","fixed":["42.0.2"],"introduced":["37.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-m758-wjhj-p3jq"},{"ecosystem":"crates.io","fixed":["43.0.1"],"introduced":["43.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-m758-wjhj-p3jq"},{"ecosystem":"crates.io","fixed":["43.0.1"],"introduced":["43.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-m758-wjhj-p3jq"}],"prev":{"headline":"Wasmtime panics when transcoding misaligned utf-16 strings","id":"CVE-2026-34942"},"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":"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":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-04-13","vendors":["bytecodealliance"]},"summary":"A guest-controlled panic in Wasmtime when lifting flags values allows attackers to cause a denial of service against the host runtime.","url":"https://insights.sbomify.com/CVE-2026-34943/"}