{"id":"CVE-2020-35859","aliases":["EUVD-2021-1537","GHSA-3933-wvjf-pcvc","RUSTSEC-2020-0004"],"status":"published","title":"Out of bounds access in lucet-runtime-internals","description":"An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust. It mishandles sigstack allocation. Guest programs may be able to obtain sensitive information, or guest programs can experience memory corruption.","severity":{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.01523,"percentile":0.74815,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-125","CWE-787"],"published":"2020-01-24T12:00:00Z","modified":"2026-06-17T03:14:28Z","fixes":[{"ecosystem":"crates.io","package":"lucet-runtime-internals","fixed_in":["0.4.3","0.5.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"lucet-runtime-internals","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.3"}]}]},{"source":"ghsa","ecosystem":"crates.io","package":"lucet-runtime-internals","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.5.0"},{"fixed":"0.5.1"}]}]},{"source":"osv","ecosystem":"crates.io","package":"lucet-runtime-internals","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.4.3"}]}]},{"source":"osv","ecosystem":"crates.io","package":"lucet-runtime-internals","ranges":[{"type":"SEMVER","events":[{"introduced":"0.5.0"},{"fixed":"0.5.1"}]}]},{"source":"osv","ecosystem":"crates.io","package":"lucet-runtime-internals","ranges":[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.4.3"},{"introduced":"0.5.0"},{"fixed":"0.5.1"}]}]}],"products":[{"vendor":"lucet-runtime-internals_project","product":"lucet-runtime-internals"}],"references":[{"url":"https://rustsec.org/advisories/RUSTSEC-2020-0004.html","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","web","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-35859","tags":["advisory"]},{"url":"https://github.com/bytecodealliance/lucet/pull/401","tags":["web"]},{"url":"https://github.com/advisories/GHSA-3933-wvjf-pcvc"},{"url":"https://github.com/fastly/lucet","tags":["package"]},{"url":"https://crates.io/crates/lucet-runtime-internals","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2020-35859","description":"An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust. It mishandles sigstack allocation. Guest programs may be able to obtain sensitive information, or guest programs can experience memory corruption.","status":"published","published":"2020-12-31T08:30:37Z","modified":"2024-08-04T17:16:12.592Z","updated_at":"2026-11-02T14:35:57.975444Z"}],"euvd":[{"id":"EUVD-2021-1537","description":"An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust. It mishandles sigstack allocation. Guest programs may be able to obtain sensitive information, or guest programs can experience memory corruption.","status":"published","published":"2020-12-31T08:30:37Z","modified":"2024-08-04T17:16:12Z","updated_at":"2026-11-03T03:07:05.241494Z"}],"ghsa":[{"id":"GHSA-3933-wvjf-pcvc","title":"Out of bounds access in lucet-runtime-internals","description":"An embedding using affected versions of lucet-runtime configured to use non-default Wasm globals sizes of more than 4KiB, or compiled in debug mode without optimizations, could leak data from the signal handler stack to guest programs. This can potentially cause data from the embedding host to leak to guest programs or cause corruption of guest program memory. This flaw was resolved by correcting the sigstack allocation logic.","status":"published","published":"2021-08-25T20:46:16Z","modified":"2023-11-10T05:02:10Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","level":"critical"}],"cwes":["CWE-125","CWE-787"],"updated_at":"2026-11-02T14:37:18.40412Z"}],"nvd":[{"id":"CVE-2020-35859","description":"An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust. It mishandles sigstack allocation. Guest programs may be able to obtain sensitive information, or guest programs can experience memory corruption.","status":"published","published":"2020-12-31T10:15:14.877Z","modified":"2026-06-17T03:14:28.77Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":6.4,"vector":"AV:N/AC:L/Au:N/C:P/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-125","CWE-787"],"updated_at":"2026-11-02T14:06:28.340168Z"}],"osv":[{"id":"GHSA-3933-wvjf-pcvc","title":"Out of bounds access in lucet-runtime-internals","description":"An embedding using affected versions of lucet-runtime configured to use non-default Wasm globals sizes of more than 4KiB, or compiled in debug mode without optimizations, could leak data from the signal handler stack to guest programs. This can potentially cause data from the embedding host to leak to guest programs or cause corruption of guest program memory. This flaw was resolved by correcting the sigstack allocation logic.","status":"published","published":"2021-08-25T20:46:16Z","modified":"2023-11-08T04:03:35.973145Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","level":"critical"}],"cwes":["CWE-125","CWE-787"],"updated_at":"2026-11-02T15:46:35.406455Z"},{"id":"RUSTSEC-2020-0004","title":"sigstack allocation bug can cause memory corruption or leak","description":"An embedding using affected versions of lucet-runtime configured to use\nnon-default Wasm globals sizes of more than 4KiB, or compiled in debug mode\nwithout optimizations, could leak data from the signal handler stack to guest\nprograms. This can potentially cause data from the embedding host to leak to\nguest programs or cause corruption of guest program memory.\n\nThis flaw was resolved by correcting the sigstack allocation logic.","status":"published","published":"2020-01-24T12:00:00Z","modified":"2023-11-08T04:03:35.973145Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H","level":"critical"}],"updated_at":"2026-11-02T15:53:39.492624Z"}]}}