{"id":"CVE-2020-24240","details":"GNU Bison before 3.7.1 has a use-after-free in _obstack_free in lib/obstack.c (called from gram_lex) when a '\\0' byte is encountered. NOTE: there is a risk only if Bison is used with untrusted input, and the observed bug happens to cause unsafe behavior with a specific compiler/architecture. The bug report was intended to show that a crash may occur in Bison itself, not that a crash may occur in code that is generated by Bison.","modified":"2026-05-18T13:28:40.438405Z","published":"2020-08-25T14:15:16.543Z","references":[{"type":"ADVISORY","url":"https://github.com/akimd/bison/compare/v3.7...v3.7.1"},{"type":"ADVISORY","url":"https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html"},{"type":"FIX","url":"https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/akimd/bison","events":[{"introduced":"0"},{"last_affected":"6675d36e2531f2573dcb8944bd9877214677e151"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"last_affected":"3.7"}],"source":"CPE_FIELD","cpe":"cpe:2.3:a:gnu:bison:3.7:*:*:*:*:*:*:*"}}],"versions":["v3.7","v3.6.93","v3.6.92","v3.6.91","v3.6.90","v3.6","v3.5.94","v3.5.93","v3.5.92","v3.5.91","v3.5.90","v3.5","v3.4.92","v3.4.91","v3.4.90","v3.4.1","v3.4","v3.3.91","v3.3.90","v3.3","v3.2.91","v3.2.90","v3.2.1","v3.2","v3.1.91","v3.1.90","v3.1","v3.0","v2.7.91","v2.7.90","v2.4","v2.3b","v2.3a","v2.1","v2.0","v1.875","v1.75","v1.49c","v1.49b","v1.49a","before-m4-back-end","after-merge-branch-1_29","pre-merge-of-1-29-branch","v1.28c","v1.28b","GNU_1_28","GNU_1_27","GNU_1_26","GNU_ORIG"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2020-24240.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"}]}