CVE-2021-33641 Use after free in byacc
A use-after-free vulnerability in byacc allows attackers to potentially execute arbitrary code or cause a denial of service via crafted input files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-33641?
CVE-2021-33641 is a high-severity use after free vulnerability in byacc, published on 20 Jan 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
When processing files, malloc stores the data of the current line. When processing comments, malloc incorrectly accesses the released memory (use after free).
Weakness: CWE-416
Which versions are affected by CVE-2021-33641?
It affects 1 product.
Products include Openeuler Byacc.
How do I fix CVE-2021-33641?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2021-33641 being exploited?
There is no known exploitation of CVE-2021-33641 in the wild and no public exploit code.
Other vulnerabilities in byacc
Sources
Also known as CLSA-2026-1782221814, GHSA-56c6-2pfc-9rvh.