CVE-2020-13943

MEDIUM
4.3
CVSS Score
Published: October 12, 2020 at 01:46 PM UTC
Updated: October 8, 2026 at 10:16 PM UTC
4 products affected across 3 vendorsTomcatDebian LinuxInstantis Enterprisetrack

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Severity
MEDIUM4.3
Exploit prediction
EPSS 53%
SSVC
No known exploit

Description

If an HTTP/2 client connecting to Apache Tomcat 10.0.0-M1 to 10.0.0-M7, 9.0.0.M1 to 9.0.37 or 8.5.0 to 8.5.57 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.

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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