PT-2020-15669 · Gnu · Gnu Bison

Suhwan Song · Published 2020-08-25 · Updated 2022-07-22 · CVE-2020-24240

Positive Technologies (AI Summary)

CVSS v2.0

7.1

High

Base vector

AV:N/AC:M/Au:N/C:N/I:N/A:C

Name of the Vulnerable Software and Affected Versions GNU Bison versions prior to 3.7.1

Description The issue arises from a use-after-free in obstack free in lib/obstack.c, which is called from gram lex, when a '0' byte is encountered. This poses a risk only if GNU Bison is used with untrusted input, and the observed bug causes unsafe behavior with a specific compiler or architecture. The bug report indicates that a crash may occur in GNU Bison itself.

Recommendations For GNU Bison versions prior to 3.7.1, update to version 3.7.1 or later to resolve the issue. As a temporary workaround, consider avoiding the use of GNU Bison with untrusted input until a patch is available.

Fix

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

CVE-2020-24240

OESA-2022-1767

Affected Products

Gnu Bison

References · 15

• https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d · Patch
• https://osv.dev/vulnerability/UBUNTU-CVE-2020-24240 · Vendor Advisory
• https://osv.dev/vulnerability/OESA-2022-1767 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2020-24240 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2020-24240 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2020-24240 · Security Note
• https://osv.dev/vulnerability/CVE-2020-24240 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2020-24240 · Security Note
• https://osv.dev/vulnerability/ALPINE-CVE-2020-24240 · Vendor Advisory
• https://ubuntu.com/security/CVE-2020-24240 · Vendor Advisory
• https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html · Vendor Advisory
• https://github.com/akimd/bison/compare/v3.7...v3.7.1 · Note
• https://security.alpinelinux.org/vuln/CVE-2020-24240 · Note
• https://openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-1767 · Note
• https://t.me/cibsecurity/21450 · Telegram Post