CVE-2020-24240
Published: 25 August 2020
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.
Priority
Status
Package | Release | Status |
---|---|---|
bison Launchpad, Ubuntu, Debian |
kinetic |
Ignored
(end of life, was needed)
|
trusty |
Does not exist
|
|
groovy |
Ignored
(end of life)
|
|
bionic |
Needed
|
|
focal |
Needed
|
|
upstream |
Released
(3.7.1)
|
|
xenial |
Needed
|
|
hirsute |
Ignored
(end of life)
|
|
jammy |
Needed
|
|
lunar |
Not vulnerable
(2:3.8.2+dfsg-1build1)
|
|
impish |
Ignored
(end of life)
|
|
mantic |
Not vulnerable
(2:3.8.2+dfsg-1build1)
|
|
Patches: upstream: https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d |
Severity score breakdown
Parameter | Value |
---|---|
Base score | 5.5 |
Attack vector | Local |
Attack complexity | Low |
Privileges required | None |
User interaction | Required |
Scope | Unchanged |
Confidentiality | None |
Integrity impact | None |
Availability impact | High |
Vector | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |