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CVE-2020-13943

MEDIUMCVSS 4.3/10EPSS 57.29%

Last modified

CVE-2020-13943 is a medium-severity vulnerability rated 4.3/10 on the CVSS scale. 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.. EPSS estimates a 57.29% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS Probability
57.29%

98.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersionsUpdate
ApacheTomcat8.5.0—
ApacheTomcat8.5.1—
ApacheTomcat8.5.2—
ApacheTomcat8.5.3—
ApacheTomcat8.5.4—
ApacheTomcat8.5.5—
ApacheTomcat8.5.6—
ApacheTomcat8.5.7—
ApacheTomcat8.5.8—
ApacheTomcat8.5.9—
ApacheTomcat8.5.10—
ApacheTomcat8.5.11—
ApacheTomcat8.5.12—
ApacheTomcat8.5.13—
ApacheTomcat8.5.14—
ApacheTomcat8.5.15—
ApacheTomcat8.5.16—
ApacheTomcat8.5.17—
ApacheTomcat8.5.18—
ApacheTomcat8.5.19—
ApacheTomcat8.5.20—
ApacheTomcat8.5.21—
ApacheTomcat8.5.22—
ApacheTomcat8.5.23—
ApacheTomcat8.5.24—
ApacheTomcat8.5.25—
ApacheTomcat8.5.26—
ApacheTomcat8.5.27—
ApacheTomcat8.5.28—
ApacheTomcat8.5.29—
ApacheTomcat8.5.30—
ApacheTomcat8.5.31—
ApacheTomcat8.5.32—
ApacheTomcat8.5.33—
ApacheTomcat8.5.34—
ApacheTomcat8.5.35—
ApacheTomcat8.5.36—
ApacheTomcat8.5.37—
ApacheTomcat8.5.38—
ApacheTomcat8.5.39—
ApacheTomcat8.5.40—
ApacheTomcat8.5.41—
ApacheTomcat8.5.42—
ApacheTomcat8.5.43—
ApacheTomcat8.5.44—
ApacheTomcat8.5.45—
ApacheTomcat8.5.46—
ApacheTomcat8.5.47—
ApacheTomcat8.5.48—
ApacheTomcat8.5.49—

Showing 50 of 103 affected configurations. See NVD for the full list.

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2020-13943?
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.
How severe is CVE-2020-13943?
CVE-2020-13943 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 57.29% probability of exploitation in the next 30 days.
How do I fix CVE-2020-13943?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-13943?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST