{"answers":{"affected":"4 open source packages ship an affected version, including wasmtime. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34983 exists.","fix":"Upgrade wasmtime to 43.0.1 or later.","what":"CVE-2026-34983 is a low-severity use after free vulnerability in bytecodealliance wasmtime, published on 9 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-34983 and fix it if it is affected.\n\nWhat it is: CVE-2026-34983 is a low-severity use after free vulnerability in bytecodealliance wasmtime, published on 9 Apr 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34983 exists.\n\nAffected packages and fixed versions:\n- wasmtime (PyPI): affected all versions up to 43.0.0; no fix listed\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- 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-2026-34983/ (Markdown: https://insights.sbomify.com/CVE-2026-34983/index.md)","id":"CVE-2026-34983","markdown":"https://insights.sbomify.com/CVE-2026-34983/index.md","name":"CVE-2026-34983","record":{"aliases":["DEBIAN-CVE-2026-34983","GHSA-hfr4-7c6c-48w2","PYSEC-2026-151","RUSTSEC-2026-0090","UBUNTU-CVE-2026-34983"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["code_execution","denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"WebAssembly runtime library","requires_auth":"high_privilege","summary":"A use-after-free vulnerability in Wasmtime allows host applications to trigger memory corruption via specific API calls, potentially leading to crashes or code execution.","user_interaction":"required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"wasmtime","vendor":"bytecodealliance"}],"cvss":{"score":1,"severity":"low","source":"cna","vector":"CVSS:4.0/AV:P/AC:H/AT:P/PR:H/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-416","name":"Use After Free"}],"description":"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.","ecosystems":["PyPI","crates.io"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Wasmtime has a use-after-free bug after cloning `wasmtime::Linker`","id":"CVE-2026-34983","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"use_after_free","year":"2026"},"n_packages":4,"n_references":1,"next":{"headline":"External Secrets Operator has DNS exfiltration via getHostByName in its v2 template engine","id":"CVE-2026-34984"},"packages":[{"ecosystem":"PyPI","fixed":[],"introduced":["0"],"last_affected":["43.0.0"],"package":"wasmtime","purl":"pkg:pypi/wasmtime","source":"PYSEC-2026-151"},{"ecosystem":"crates.io","fixed":["43.0.1"],"introduced":["43.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-hfr4-7c6c-48w2"},{"ecosystem":"crates.io","fixed":["43.0.1"],"introduced":["43.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-hfr4-7c6c-48w2"},{"ecosystem":"crates.io","fixed":["43.0.1"],"introduced":["43.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"RUSTSEC-2026-0090"}],"prev":{"headline":"Vim modeline bypass via various options affects Vim \u003c 9.2.0276","id":"CVE-2026-34982"},"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":"attribution","licence":"CC BY 4.0","name":"PyPA Advisory Database","prefix":"PYSEC"},{"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":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-04-13","vendors":["bytecodealliance"]},"summary":"A use-after-free vulnerability in Wasmtime allows host applications to trigger memory corruption via specific API calls, potentially leading to crashes or code execution.","url":"https://insights.sbomify.com/CVE-2026-34983/"}