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CVE-2020-13935 Apache Tomcat

Affected softwareApache Tomcat
Severity7.5 High CVSS 3.1 2 scores
Fixed in10.0.0-M7, 9.0.37, 8.5.57, 7.0.105
WeaknessCWE-835
Published14 Jul 2020
Updated8 Oct 2026

Description

The payload length in a WebSocket frame was not correctly validated in Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M1 to 9.0.36, 8.5.0 to 8.5.56 and 7.0.27 to 7.0.104. Invalid payload lengths could trigger an infinite loop. Multiple requests with invalid payload lengths could lead to a denial of service.

Exploitation status

Working exploit published

A reviewed exploit catalogue lists ready-to-run exploit code for this CVE.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: none
  • Indexed PoC 2 indexed Published artifacts you can open, in GitHub PoC, Nuclei; first seen 2020-11-02.
  • EPSS 87% chance in 30 days A model's forecast, not a report of exploitation. Higher than 99.7% of all scored CVEs.
IndexArtifactStarsFirst seen
GitHub PoC Exploit for WebSocket Vulnerability in Apache Tomcat 167 2020-11-02
Nuclei Apache Tomcat WebSocket Frame Payload Length Validation Denial of Service

Waratek protection

Mitigation candidate

A kind of vulnerability Waratek's rules address, with exploit code published or exploitation reported. No rule exists and none is planned yet. The decision below says what we found to build a rule from.

  • Protection none
  • Action unverified
  • Review automated Inferred
  • Record active
Decided by The affected package being open source on Maven, so the fix can be read
Finding This CVE affects an open-source Java library published on Maven Central (Maven packages: org.apache.tomcat:tomcat, org.apache.tomcat.embed:tomcat-embed-websocket, org.apache.tomcat:tomcat-websocket), so it is squarely in ARMR's territory and the source needed to understand the defect is public. That makes it a candidate for an ARMR patch rule. No rule exists and none is scheduled: the diff between the affected and fixed versions has not been read, and a closer look may find no hook point ARMR can act on.

CVSS

7.5 HIGH v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H NVD Primary published
CVSS 2.0 5.0 none AV:N/AC:L/Au:N/C:N/I:N/A:P NVD Primary

Affected software and releases

Oracle advisories

AdvisoryTypeQuarterProducts Oracle names in its risk matrix
Oracle Critical Patch Update April 2025 ↗ CPU 2025-Q2 Oracle Autonomous Health Framework / Trace File Analyzer (Apache Tomcat) (23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0)
Oracle Critical Patch Update January 2022 ↗ CPU 2022-Q1 Oracle Commerce / Endeca Application Controller (Apache Tomcat) (11.3.2)
Oracle Critical Patch Update July 2021 ↗ CPU 2021-Q3 Oracle Supply Chain / Installation Issues (Apache Tomcat) (6.2.1.0)
Oracle Critical Patch Update January 2021 ↗ CPU 2021-Q1 Oracle Fusion Middleware / MFT Runtime Server (Apache Tomcat) (12.2.1.3.0, 12.2.1.4.0)
Oracle Critical Patch Update October 2020 ↗ CPU 2020-Q4 Oracle Construction and Engineering / Core (Apache Tomcat) (17.1, 17.2, 17.3)
Oracle Database Server / Workload Manager (Apache Tomcat) (12.2.0.1, 18c, 19c)
Oracle MySQL / Monitoring: General (Apache Tomcat) (8.0.21 and prior)

Oracle components and versions

FamilyComponentVersions, as Oracle lists themRead as
Oracle Autonomous Health Framework Trace File Analyzer (Apache Tomcat) 23.8.0-23.11.0, 24.1.0-24.11.0, 25.1.0, 25.2.0 25.1.0 · 25.2.0
Oracle Commerce Endeca Application Controller (Apache Tomcat) 11.3.2 11.3.2
Oracle Construction and Engineering Core (Apache Tomcat) 17.1, 17.2, 17.3 17.1 · 17.2 · 17.3
Oracle Database Server Workload Manager (Apache Tomcat) 12.2.0.1, 18c, 19c 12.2.0.1 · 18 · 19
Oracle Fusion Middleware MFT Runtime Server (Apache Tomcat) 12.2.1.3.0, 12.2.1.4.0 12.2.1.3.0 · 12.2.1.4.0
Oracle MySQL Monitoring: General (Apache Tomcat) 8.0.21 and prior
Oracle Supply Chain Installation Issues (Apache Tomcat) 6.2.1.0 6.2.1.0

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
org.apache.tomcat:tomcat 10.0.0-M1 10.0.0-M7 unbounded
org.apache.tomcat:tomcat 9.0.0.M1 9.0.37 unbounded
org.apache.tomcat:tomcat 8.5.0 8.5.57 unbounded
org.apache.tomcat:tomcat 7.0.27 7.0.105 unbounded
org.apache.tomcat.embed:tomcat-embed-websocket 7.0.27 7.0.105 unbounded
org.apache.tomcat.embed:tomcat-embed-websocket 8.5.0 8.5.57 unbounded
org.apache.tomcat.embed:tomcat-embed-websocket 9.0.0.M1 9.0.37 unbounded
org.apache.tomcat.embed:tomcat-embed-websocket 10.0.0-M1 10.0.0-M7 unbounded
org.apache.tomcat:tomcat-websocket 10.0.0-M1 10.0.0-M7 unbounded
org.apache.tomcat:tomcat-websocket 9.0.0.M1 9.0.37 unbounded
org.apache.tomcat:tomcat-websocket 8.5.0 8.5.57 unbounded
org.apache.tomcat:tomcat-websocket 7.0.27 7.0.105 unbounded

Products and versions

21 products, 86 version entries
SourceVendorProductSchemeAffected versions
nvd apache tomcat generic ≥ 7.0.27 and ≤ 7.0.104 · ≥ 8.5.0 and ≤ 8.5.56 · 9.0.0:milestone1 · 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:milestone2 · 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:milestone3 · 9.0.0:milestone4 · 9.0.0:milestone5 · 9.0.0:milestone6 · 9.0.0:milestone7 · 9.0.0:milestone8 · 9.0.0:milestone9 · ≥ 9.0.1 and ≤ 9.0.36 · 10.0.0:milestone1 · 10.0.0:milestone2 · 10.0.0:milestone3 · 10.0.0:milestone4 · 10.0.0:milestone5 · 10.0.0:milestone6
nvd canonical ubuntu linux generic 16.04 · 20.04
nvd debian debian linux generic 9.0 · 10.0
nvd mcafee epolicy orchestrator generic 5.9.0 · 5.9.1 · 5.10.0 · 5.10.0:update_1 · 5.10.0:update_2 · 5.10.0:update_3 · 5.10.0:update_4 · 5.10.0:update_5 · 5.10.0:update_6 · 5.10.0:update_7 · 5.10.0:update_8
nvd netapp oncommand system manager generic ≥ 3.0.0 and ≤ 3.1.3
nvd opensuse leap generic 15.1 · 15.2
nvd oracle agile engineering data management generic 6.2.1.0
nvd oracle agile product lifecycle management generic 9.3.3 · 9.3.5 · 9.3.6
nvd oracle blockchain platform generic < 21.1.2
nvd oracle commerce guided search generic 11.3.2
nvd oracle communications cloud native core policy generic 1.14.0
nvd oracle communications instant messaging server generic 10.0.1.5.0
nvd oracle fmw platform generic 12.2.1.3.0 · 12.2.1.4.0
nvd oracle instantis enterprisetrack generic 17.1 · 17.2 · 17.3
nvd oracle managed file transfer generic 12.2.1.3.0 · 12.2.1.4.0
nvd oracle mysql enterprise monitor generic ≤ 8.0.21
nvd oracle siebel ui framework generic ≤ 20.12
nvd oracle workload manager generic 12.2.0.1 · 18c · 19c
osv org.apache.tomcat tomcat generic ≥ 7.0.27 and < 7.0.105 · ≥ 8.5.0 and < 8.5.57 · ≥ 9.0.0 and < 9.0.37 · ≥ 10.0.0 and < 10.0.0
osv org.apache.tomcat tomcat-websocket generic ≥ 7.0.27 and < 7.0.105 · ≥ 8.5.0 and < 8.5.57 · ≥ 9.0.0 and < 9.0.37 · ≥ 10.0.0 and < 10.0.0
osv org.apache.tomcat.embed tomcat-embed-websocket generic ≥ 7.0.27 and < 7.0.105 · ≥ 8.5.0 and < 8.5.57 · ≥ 9.0.0 and < 9.0.37 · ≥ 10.0.0 and < 10.0.0

References

URLTags
https://github.com/apache/tomcat/commit/12d715676038efbf9c728af10163f8277fc019d5 WEB
https://github.com/apache/tomcat/commit/1c1c77b0efb667cea80b532440b44cea1dc427c3 WEB
https://github.com/apache/tomcat/commit/40fa74c74822711ab878079d0a69f7357926723d WEB
https://github.com/apache/tomcat/commit/4c04982870d6e730c38e21e58fb653b7cf723784 WEB
https://github.com/apache/tomcat/commit/f9f75c14678b68633f79030ddf4ff827f014cc84 WEB
https://tomcat.apache.org/security-9.html WEB
https://usn.ubuntu.com/4448-1 WEB
https://usn.ubuntu.com/4596-1 WEB
https://www.debian.org/security/2020/dsa-4727 WEB
https://www.oracle.com//security-alerts/cpujul2021.html WEB

Timeline

Published2020-07-14By the CVE Program.
NVD record modified2026-10-08NVD's own last-modified date for this record.