4.3

CVE-2020-13943: apache tomcat

Modified
AliasesMGASA-2020-0397SUSE-SU-2020:2996-1SUSE-SU-2020:3068-1
Published 12-10-2020Last modified 08-10-2026

Vulnerability summary

CVE-2020-13943 is a medium (CVSS 4.3) vulnerability in apache tomcat. EPSS estimates a 52.64% chance of exploitation in the next 30 days, higher than 98.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 4.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
4.3/10
010
Medium · v3.1 (NVD)
EPSS score
52.64%
0%100%
Critical · -4.65 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 4
DSA-4835-1OPENSUSE-SU-2024:11468-1OPENSUSE-SU-2024:13441-1RHSA-2021:0494SUSE-SU-2021:0040-1SUSE-SU-2026:1058-1

Timeline

  1. 12-10-2020
    PublishedVulnerability first disclosed.
  2. 08-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

52.64%

Chance of exploitation in the next 30 days

Percentile

99%

Versus all other CVEs

30-day change

Decrease -4.65 pp

From 57.29% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Suse4 products
  • tomcat&distro=SUSE Linux Enterprise Module for Web and Scripting 15 SP1< 9.0.36-4.47.3
  • tomcat&distro=SUSE Linux Enterprise Module for Web and Scripting 15 SP2< 9.0.36-3.12.3
  • tomcat&distro=SUSE Linux Enterprise Server 12 SP5< 9.0.36-3.50.1
  • tomcat&distro=SUSE Linux Enterprise Server for SAP Applications 12 SP5< 9.0.36-3.50.1
Debian3 products
  • tomcat8< 8.5.54-0+deb9u4
  • tomcat9< 9.0.38-1
  • debian_linuxEOL9.0 | 10.0
Opensuse2 products
  • tomcat&distro=openSUSE Leap 15.1< 9.0.36-lp151.3.33.1
  • tomcat&distro=openSUSE Leap 15.2< 9.0.36-lp152.2.10.1
Oracle2 products
Apache1 product
  • tomcatEOL8.5.0 | 8.5.1 | 8.5.2 | 8.5.3 | 8.5.4 | 8.5.5 | 8.5.6 | 8.5.7 | 8.5.8 | 8.5.9 | 8.5.10 | 8.5.11 | 8.5.12 | 8.5.13 | 8.5.14 | 8.5.15 | 8.5.16 | 8.5.17 | 8.5.18 | 8.5.19 | 8.5.20 | 8.5.21 | 8.5.22 | 8.5.23 | 8.5.24 | 8.5.25 | 8.5.26 | 8.5.27 | 8.5.28 | 8.5.29 | 8.5.30 | 8.5.31 | 8.5.32 | 8.5.33 | 8.5.34 | 8.5.35 | 8.5.36 | 8.5.37 | 8.5.38 | 8.5.39 | 8.5.40 | 8.5.41 | 8.5.42 | 8.5.43 | 8.5.44 | 8.5.45 | 8.5.46 | 8.5.47 | 8.5.48 | 8.5.49 | 8.5.50 | 8.5.51 | 8.5.52 | 8.5.53 | 8.5.54 | 8.5.55 | 8.5.56 | 8.5.57 | 9.0.0:milestone10 | 9.0.0:milestone11 | 9.0.0:milestone12 | 9.0.0:milestone13 | 9.0.0:milestone14 | 9.0.0:milestone15 | 9.0.0:milestone16 | 9.0.0:milestone17 | 9.0.0:milestone18 | 9.0.0:milestone19 | 9.0.0:milestone20 | 9.0.0:milestone21 | 9.0.0:milestone22 | 9.0.0:milestone23 | 9.0.0:milestone24 | 9.0.0:milestone25 | 9.0.0:milestone26 | 9.0.0:milestone27 | 9.0.0:milestone5 | 9.0.0:milestone6 | 9.0.0:milestone7 | 9.0.0:milestone8 | 9.0.0:milestone9 | 9.0.1 | 9.0.2 | 9.0.3 | 9.0.4 | 9.0.5 | 9.0.6 | 9.0.7 | 9.0.8 | 9.0.9 | 9.0.10 | 9.0.11 | 9.0.12 | 9.0.13 | 9.0.14 | 9.0.15 | 9.0.16 | 9.0.17 | 9.0.18 | 9.0.19 | 9.0.20 | 9.0.21 | 9.0.22 | 9.0.23 | 9.0.24 | 9.0.25 | 9.0.26 | 9.0.27 | 9.0.28 | 9.0.29 | 9.0.30 | 9.0.31 | 9.0.32 | 9.0.33 | 9.0.34 | 9.0.35 | 9.0.36 | 9.0.37 | 10.0.0:milestone1 | 10.0.0:milestone2 | 10.0.0:milestone3 | 10.0.0:milestone4 | 10.0.0:milestone5 | 10.0.0:milestone6 | 10.0.0:milestone7
Mageia1 product
  • tomcat< 9.0.38-1.mga7
Org.apache.tomcat1 product
  • tomcat-coyote≥ 10.0.0-M1, < 10.0.0-M8 | ≥ 9.0.0-M1, < 9.0.38 | ≥ 8.5.0, < 8.5.58

7 vendors · 14 products

References

24 links
Show all 24 references