#VU46312 Heap-based buffer overflow in GNU Bison - CVE-2020-24979

Vulnerability identifier: #VU46312

Vulnerability risk: Medium

CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-24979

CWE-ID: CWE-122

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
GNU Bison
Other software / Other software solutions

Vendor: GNU

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a boundary error in src/symtab.c in GNU bison when processing files. A remote attacker can trick the victim to open a specially crafted file that redefines the EOF token, trigger heap-based buffer overflow and crash the application.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

GNU Bison: 3.7 - 3.7.1

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External links
https://github.com/akimd/bison/commit/bfd851e2d621734886c66c0af26e861e718510b2
https://lists.gnu.org/r/bug-bison/2020-08/msg00008.html

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Q & A

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.