CVE-2021-40438 Apache Apache: web page flaw
In plain words: A web app can be made to act on someone's behalf or reach places it should not. Stolen sessions, actions taken as the victim, or access to internal systems.
Confirmed exploited by CISA on · US federal patch deadline Dec 15, 2021
What to do
- Install Apache's security update for Apache. 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 HTTP Server-Side Request Forgery (SSRF)
- Product
- Apache Apache
- CISA description
- A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.
- Type of flaw
- Web page flaw (CWE-918)
- Confirmed exploited
- Dec 1, 2021 — known to be used in ransomware attacks
- US federal patch deadline
- Dec 15, 2021
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Answering about CVE-2021-40438 ·
Questions about CVE-2021-40438
Is CVE-2021-40438 being exploited?
Yes. CISA added CVE-2021-40438 to its Known Exploited Vulnerabilities catalog on Dec 1, 2021, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2021-40438?
Install Apache's security update for Apache. 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-2021-40438?
Only if you use Apache Apache. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.