{"answers":{"affected":"5 open source packages ship an affected version, including wasmtime.","exploited":"There is no known exploitation of CVE-2026-115889 in the wild and no public exploit code.","fix":"Upgrade wasmtime to a fixed version for your release line: 36.0.19 or 43.0.0.","what":"CVE-2026-115889 is a critical vulnerability in bytecodealliance wasmtime, published on 23 Oct 2026."},"fix_prompt":"Check this codebase for CVE-2026-115889 and fix it if it is affected.\n\nWhat it is: CVE-2026-115889 is a critical vulnerability in bytecodealliance wasmtime, published on 23 Oct 2026. \nExploitation: There is no known exploitation of CVE-2026-115889 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- wasmtime (crates.io): affected all versions; fixed in 36.0.19\n- wasmtime (crates.io): affected all versions; fixed in 36.0.19\n- wasmtime (crates.io): affected from 0.0.0-0; fixed in 36.0.19, 43.0.0\n- wasmtime (crates.io): affected from 37.0.0; fixed in 43.0.0\n- wasmtime (crates.io): affected from 37.0.0; fixed in 43.0.0\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-2026-115889/ (Markdown: https://insights.sbomify.com/CVE-2026-115889/index.md)","id":"CVE-2026-115889","markdown":"https://insights.sbomify.com/CVE-2026-115889/index.md","name":"CVE-2026-115889","record":{"aliases":["AZL-111431","AZL-111437","DEBIAN-CVE-2026-115889","GHSA-897f-g5gm-fmxm","RUSTSEC-2026-0380","UBUNTU-CVE-2026-115889"],"analysis":null,"analysis_generated_by":null,"assigner":"GitHub_M","cpe":[],"cvss":{"score":9.9,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-843","name":"Access of Resource Using Incompatible Type"},{"id":"CWE-197","name":"Numeric Truncation Error"}],"description":"Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend. This issue is fixed in versions 36.0.19 and 43.0.0.","ecosystems":["crates.io"],"exploits":{"exploitdb":0,"first_seen":"2026-10-27","github_poc":2,"max_poc_stars":0,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-10-27T14:25:05Z","kind":"github_poc","ref":"https://github.com/ideator-labs/wasmtime-sweep","stars":0,"title":"Find every Wasmtime engine embedded in binaries, wheels, NuGet packages and layers, and check CVE-2026-115889/115893"},{"date":"2026-10-29T10:50:55Z","kind":"github_poc","ref":"https://github.com/mehmet-emir-eroglu/CVE-2026-115889","stars":0,"title":"Offline Python detector for CVE-2026-115889 version exposure in Wasmtime."}],"tier":"poc_unverified"},"has_fix":true,"headline":"Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation","id":"CVE-2026-115889","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"crates.io","product":null,"products":[],"type":null,"year":"2026"},"n_packages":5,"n_references":7,"next":{"headline":"Wasmtime: Panic lowering a host-created component model stream into a guest that expects a different payload type","id":"CVE-2026-115892"},"packages":[{"ecosystem":"crates.io","fixed":["36.0.19"],"introduced":["0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-897f-g5gm-fmxm"},{"ecosystem":"crates.io","fixed":["36.0.19"],"introduced":["0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-897f-g5gm-fmxm"},{"ecosystem":"crates.io","fixed":["36.0.19","43.0.0"],"introduced":["0.0.0-0","37.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"RUSTSEC-2026-0380"},{"ecosystem":"crates.io","fixed":["43.0.0"],"introduced":["37.0.0"],"last_affected":[],"package":"wasmtime","purl":null,"source":"GHSA-897f-g5gm-fmxm"},{"ecosystem":"crates.io","fixed":["43.0.0"],"introduced":["37.0.0"],"last_affected":[],"package":"wasmtime","purl":"pkg:cargo/wasmtime","source":"GHSA-897f-g5gm-fmxm"}],"prev":{"headline":"graphql-scalars PhoneNumber scalar is vulnerable to regular expression denial of service","id":"CVE-2026-115887"},"products":["wasmtime"],"published":"2026-10-23","related":[],"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":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-10-26","vendors":["bytecodealliance"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-115889/"}