CVE-2020-24240
GNU Bison Use-After-Free Vulnerability
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.
INFO
Published Date :
Aug. 25, 2020, 2:15 p.m.
Last Modified :
Nov. 21, 2024, 5:14 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | HIGH | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update GNU Bison to a version greater than 3.7.
- Reboot the system after the update.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2020-24240.
| URL | Resource |
|---|---|
| https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d | Patch Third Party Advisory |
| https://github.com/akimd/bison/compare/v3.7...v3.7.1 | Third Party Advisory |
| https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html | Mailing List Vendor Advisory |
| https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d | Patch Third Party Advisory |
| https://github.com/akimd/bison/compare/v3.7...v3.7.1 | Third Party Advisory |
| https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html | Mailing List Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2020-24240 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2020-24240
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2020-24240 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2020-24240 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d Added Reference https://github.com/akimd/bison/compare/v3.7...v3.7.1 Added Reference https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html -
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Initial Analysis by [email protected]
Sep. 02, 2020
Action Type Old Value New Value Added CVSS V2 Metadata Victim must voluntarily interact with attack mechanism Added CVSS V2 NIST (AV:N/AC:M/Au:N/C:N/I:N/A:C) Added CVSS V3.1 NIST AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Changed Reference Type https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d No Types Assigned https://github.com/akimd/bison/commit/be95a4fe2951374676efc9454ffee8638faaf68d Patch, Third Party Advisory Changed Reference Type https://github.com/akimd/bison/compare/v3.7...v3.7.1 No Types Assigned https://github.com/akimd/bison/compare/v3.7...v3.7.1 Third Party Advisory Changed Reference Type https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html No Types Assigned https://lists.gnu.org/r/bug-bison/2020-07/msg00051.html Mailing List, Vendor Advisory Added CWE NIST CWE-416 Added CPE Configuration OR *cpe:2.3:a:gnu:bison:3.7:*:*:*:*:*:*:* -
CVE Modified by [email protected]
Aug. 31, 2020
Action Type Old Value New Value Changed Description GNU Bison 3.7 has a use after free (UAF) vulnerability. A local attacker may execute bison with crafted input file containing a NULL byte, which could triggers UAF and thus cause system crash. 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. Added Reference https://github.com/akimd/bison/compare/v3.7...v3.7.1 [No Types Assigned]
Vulnerability Scoring Details
Base CVSS Score: 5.5
Base CVSS Score: 7.1
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.42 }} -0.50%
score
0.59096
percentile