CVE-2020-24240
5.5
MEDIUM
CVSS 3.1
EPSS 0.24%
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.
How to fix CVE-2020-24240
To remediate CVE-2020-24240, upgrade the affected package to a fixed version below.
- —upgrade to 3.7.2-r0 or later
- —upgrade to 2:3.7.2+dfsg-1 or later
Is CVE-2020-24240 being exploited?
Low — EPSS is 0.2%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 3.7.2-r0
- from 0, < 2:3.7.2+dfsg-1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |