CVE-2020-24240 Information

Description

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.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Reference

https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d https://github.com/akimd/bison/compare/v3.7…v3.7.1 https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.5