CVE-2021-46878 Use after free in n/a
An attacker can execute arbitrary code by tricking a user into opening a crafted file, exploiting a use-after-free vulnerability in Fluent Bit's msgpack parsing.
- 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-2021-46878?
CVE-2021-46878 is a high-severity use after free vulnerability in n/a, published on 11 Apr 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
An issue was discovered in Treasure Data Fluent Bit 1.7.1, erroneous parsing in flb_pack_msgpack_to_json_format leads to type confusion bug that interprets whatever is on the stack as msgpack maps and arrays, leading to use-after-free. This can be used by an attacker to craft a specially craft file and trick the victim opening it using the affect software, triggering use-after-free and execute arbitrary code on the target system.
Weakness: CWE-843
Which versions are affected by CVE-2021-46878?
1 open source package ship an affected version, including fluent-bit. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
fluent-bit Bitnami | From 1.7.1 | 1.7.2 |
Products include Treasuredata Fluent Bit.
How do I fix CVE-2021-46878?
Upgrade fluent-bit to 1.7.2 or later.
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-2021-46878 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-46878 exists.
Other vulnerabilities in n/a
Sources
Also known as BIT-fluent-bit-2021-46878, GHSA-r3hq-4h29-qfq9.