#VU47516 Resource management error in Apache Tomcat - CVE-2020-13943

Vulnerability identifier: #VU47516

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-13943

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Apache Tomcat
Server applications / Web servers

Vendor: Apache Foundation

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists due to improper management of internal resources within the application when processing HTTP/2 requests. If an HTTP/2 client exceeded the agreed maximum number of concurrent streams for a connection (in violation of the HTTP/2 protocol), it was possible that a subsequent request made on that connection could contain HTTP headers - including HTTP/2 pseudo headers - from a previous request rather than the intended headers. This could lead to users seeing responses for unexpected resources.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Apache Tomcat: 8.5.0 - 8.5.57, 9.0.0-M1 - 9.0.37, 10.0.0-M1 - 10.0.0.0-M1

---

External links
https://seclists.org/oss-sec/2020/q4/42

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.