CVE-2020-5243 Denial of Service in uap-core when processing crafted User-Agent strings
Remote attackers can cause denial of service in uap-core by sending crafted User-Agent strings that trigger excessive CPU usage via regex backtracking.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2020-5243?
CVE-2020-5243 is a medium-severity denial of service vulnerability in ua-parser uap-core, published on 20 Feb 2020. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
uap-core before 0.7.3 is vulnerable to a denial of service attack when processing crafted User-Agent strings. Some regexes are vulnerable to regular expression denial of service (REDoS) due to overlapping capture groups. This allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to maliciously crafted long strings. This has been patched in uap-core 0.7.3.
Which versions are affected by CVE-2020-5243?
4 open source packages ship an affected version, including uap-core and user_agent_parser. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
uap-core npm | All versions | 0.7.3 |
uap-core npm | All versions | 0.7.3 |
user_agent_parser RubyGems | All versions | 2.6.0 |
user_agent_parser RubyGems | All versions | 2.6.0 |
Products include Uap-Core Project Uap-Core.
How do I fix CVE-2020-5243?
Upgrade uap-core to 0.7.3 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2020-5243 being exploited?
There is no known exploitation of CVE-2020-5243 in the wild and no public exploit code.
Other vulnerabilities in ua-parser uap-core
Sources
Also known as DEBIAN-CVE-2020-5243, GHSA-cmcx-xhr8-3w9p, UBUNTU-CVE-2020-5243.