CVE-2021-45046 Apache Log4j2: command or code injection
In plain words: The program treats text it receives as instructions instead of plain data. The attacker can run commands on the machine — often the whole device is taken over.
Confirmed exploited by CISA on · US federal patch deadline May 22, 2023
What to do
- Install Apache's security update for Log4j2. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- Apache Log4j2 Deserialization of Untrusted Data Vulnerability
- Product
- Apache Log4j2
- CISA description
- Apache Log4j2 contains a deserialization of untrusted data vulnerability due to the incomplete fix of CVE-2021-44228, where the Thread Context Lookup Pattern is vulnerable to remote code execution in certain non-default configurations.
- Type of flaw
- Command or code injection (CWE-917)
- Confirmed exploited
- May 1, 2023 — known to be used in ransomware attacks
- US federal patch deadline
- May 22, 2023
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Answering about CVE-2021-45046 ·
Questions about CVE-2021-45046
Is CVE-2021-45046 being exploited?
Yes. CISA added CVE-2021-45046 to its Known Exploited Vulnerabilities catalog on May 1, 2023, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2021-45046?
Install Apache's security update for Log4j2. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2021-45046?
Only if you use Apache Log4j2. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.