Vulnerability identifier: #VU46310
Vulnerability risk: Medium
CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID:
CWE-ID:
CWE-416
Exploitation vector: Network
Exploit availability: No
Vulnerable software:
GNU Bison
Other software /
Other software solutions
Vendor: GNU
Description
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
GNU Bison before 3.7.1 has a use-after-free in _obstack_free in lib/obstack.c (called from gram_lex) when a '�' 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.
Mitigation
Install update from vendor's website.
Vulnerable software versions
GNU Bison: 3.7
External links
http://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d
http://github.com/akimd/bison/compare/v3.7...v3.7.1
http://lists.gnu.org/r/bug-bison/2020-07/msg00051.html
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.