CVE-2020-24240

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.

Category

5.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.42%
Vendor Advisory gnu.org
Affected: n/a n/a
Published at:
Updated at:

References

Link Tags
https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d third party advisory patch
https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html mailing list vendor advisory
https://github.com/akimd/bison/compare/v3.7...v3.7.1 third party advisory

Frequently Asked Questions

What is the severity of CVE-2020-24240?
CVE-2020-24240 has been scored as a medium severity vulnerability.
How to fix CVE-2020-24240?
To fix CVE-2020-24240, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-24240 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2020-24240 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
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