CVE-2020-13935

CRITICALNVD 7.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because EPSS predicts 87% probability of exploitation within the next 30 days (top 0.3% of all CVEs). NVD baseline CVSS 7.5 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, nvd
Elevated
9.0EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • 575 internet-exposed hosts are running an affected version right now
  • High exploitation likelihood — EPSS 87%
CISA-KEV: Not listedEPSS PROB: 87%CVSS: 7.5Exploit: Elevated riskExposed: 575

A fix is available — apply it.

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.

Live · internet exposure

575 internet-exposed hosts are running an affected version of CVE-2020-13935 right now.

across 59 countries (China, United States, Germany, Korea, Republic of, France)top: tomcat
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v3
7.5
EG Score
9.0(high)
EG Risk
80(Track)
EG Risk 80/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation87% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
87%
EPSS %ILE
100%
KEV
Not listed

Published

July 14, 2020

Last Modified

August 25, 2026

Advisory Details (5)

Auto-updated Aug 25, 2026
Patch available.
generic

[SECURITY] [DSA 4627-1] tomcat9 security update

https://www.debian.org/security/2020/dsa-4727
generic

NetApp Product Security

https://security.netapp.com/advisory/ntap-20200724-0003/
generic Patch Available

[SECURITY] [DLA 2286-1] tomcat8 security update

https://lists.debian.org/debian-lts-announce/2020/07/msg00017.html
generic
https://lists.apache.org/thread.html/rd48c72bd3255bda87564d4da3791517c074d94f8a701f93b85752651%40%3Cannounce.tomcat.apache.org%3E
generic
https://lists.apache.org/thread.html/r4e5d3c09f4dd2923191e972408b40fb8b42dbff0bc7904d44b651e50%40%3Cusers.tomcat.apache.org%3E

Vendor Advisories for CVE-2020-13935(9)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(11)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntutomcat9-user (9.0.31-1ubuntu0.1) @ focal2026-08-25ubuntu
ubuntutomcat8-user (8.0.32-1ubuntu1.13) @ xenial2026-08-25ubuntu
redhatpatch2022-06-30redhat
redhatjbossweb-0:7.5.32-2.Final_redhat_1.2.ep6.el62022-06-30redhat
redhatjbossweb-0:7.5.32-2.Final_redhat_1.2.ep6.el72022-06-30redhat
redhattomcat2021-08-11redhat
redhattomcat-0:7.0.76-15.el72020-09-29redhat
redhatjbossweb-0:7.5.31-2.Final_redhat_2.1.ep6.el72020-08-10redhat
redhatjbossweb2020-08-10redhat
redhattomcat8-0:8.0.36-45.ep7.el72020-08-04redhat
redhatjws5-tomcat-0:9.0.30-5.redhat_6.1.el8jws2020-08-04redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(9 across 7 ecosystems)
Maven(3)
PackageVulnerable rangeFixed inDependents
org.apache.tomcat.embed:tomcat-embed-websocket10.0.0-M1, 10.0.0-M3, 10.0.0-M4, 10.0.0-M5, 10.0.0-M610.0.0-M7—
org.apache.tomcat:tomcat7.0.100 ... 7.0.99 (47 versions)7.0.105—
org.apache.tomcat:tomcat-websocket8.5.0 ... 8.5.9 (45 versions)7.0.105—
Debian:10(1)
PackageVulnerable rangeFixed inDependents
tomcat99.0.16-4 ... 9.0.31-1~deb10u1 (7 versions)9.0.31-1~deb10u2—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
tomcat9—9.0.37-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
tomcat9—9.0.37-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
tomcat9—9.0.37-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
tomcat9—9.0.37-1—
Debian:9(1)
PackageVulnerable rangeFixed inDependents
tomcat88.5.14-1 ... 8.5.54-0+deb9u2 (39 versions)8.5.54-0+deb9u3—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(6)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 4× in last 7d / 14× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-06 13:44 UTCEPSS rescore
  2. 2026-09-05 15:24 UTCEPSS rescore
  3. 2026-09-04 13:56 UTCEPSS rescore
  4. 2026-09-04 05:03 UTCEPSS rescore
  5. 2026-09-01 03:32 UTCEPSS rescore
  6. 2026-08-30 19:14 UTCEPSS rescore
  7. 2026-08-28 21:37 UTCEPSS rescore
  8. 2026-08-26 14:42 UTCEPSS rescore
  9. 2026-08-25 16:36 UTCEG score recompute
  10. 2026-08-25 16:36 UTCVendor advisory
  11. 2026-08-20 22:51 UTCEPSS rescore
  12. 2026-08-20 16:01 UTCOSV refresh
  13. 2026-08-16 02:11 UTCEPSS rescore
  14. 2026-08-12 13:47 UTCEPSS rescore
  15. 2026-08-07 16:23 UTCEPSS rescore
  16. 2026-08-05 10:11 UTCOSV refresh
  17. 2026-08-02 02:23 UTCEPSS rescore
  18. 2026-07-30 16:24 UTCEPSS rescore
  19. 2026-07-25 14:14 UTCEPSS rescore
  20. 2026-07-24 14:14 UTCEPSS rescore
  21. 2026-07-23 14:15 UTCEPSS rescore
  22. 2026-07-23 14:15 UTCEPSS rescore
  23. 2026-07-23 01:49 UTCEG score recompute
  24. 2026-07-22 22:34 UTCEG score recompute
  25. 2026-07-22 14:05 UTCEPSS rescore
Show 45 more
  1. 2026-07-20 17:04 UTCEPSS rescore
  2. 2026-07-19 09:22 UTCOSV refresh
  3. 2026-07-15 16:55 UTCEPSS rescore
  4. 2026-07-13 06:10 UTCEPSS rescore
  5. 2026-07-13 06:10 UTCEPSS rescore
  6. 2026-07-06 02:20 UTCEPSS rescore
  7. 2026-07-01 15:03 UTCEPSS rescore
  8. 2026-07-01 15:03 UTCEPSS rescore
  9. 2026-07-01 15:01 UTCOSV refresh
  10. 2026-06-25 13:47 UTCEPSS rescore
  11. 2026-06-25 13:47 UTCEPSS rescore
  12. 2026-06-23 21:31 UTCEPSS rescore
  13. 2026-06-23 21:31 UTCEPSS rescore
  14. 2026-06-16 17:50 UTCEPSS rescore
  15. 2026-06-16 17:50 UTCEPSS rescore
  16. 2026-06-15 17:46 UTCEPSS rescore
  17. 2026-06-13 23:43 UTCOSV refresh
  18. 2026-06-13 22:58 UTCEPSS rescore
  19. 2026-06-13 22:58 UTCEPSS rescore
  20. 2026-06-12 23:09 UTCEPSS rescore
  21. 2026-06-10 22:16 UTCEPSS rescore
  22. 2026-06-10 22:16 UTCEPSS rescore
  23. 2026-06-08 14:15 UTCEPSS rescore
  24. 2026-06-08 14:15 UTCEPSS rescore
  25. 2026-06-07 15:23 UTCEPSS rescore
  26. 2026-06-07 15:23 UTCEPSS rescore
  27. 2026-06-06 13:45 UTCEPSS rescore
  28. 2026-06-06 13:45 UTCEPSS rescore
  29. 2026-06-06 13:45 UTCEPSS rescore
  30. 2026-06-04 13:10 UTCEPSS rescore
  31. 2026-06-04 13:10 UTCEPSS rescore
  32. 2026-06-01 13:50 UTCEPSS rescore
  33. 2026-05-31 22:29 UTCEPSS rescore
  34. 2026-05-31 22:29 UTCEPSS rescore
  35. 2026-05-29 13:42 UTCEPSS rescore
  36. 2026-05-29 13:42 UTCEPSS rescore
  37. 2026-05-28 13:43 UTCEPSS rescore
  38. 2026-05-28 13:43 UTCEPSS rescore
  39. 2026-05-27 01:26 UTCEG score recompute
  40. 2026-05-27 01:26 UTCVendor advisory
  41. 2026-05-26 20:44 UTCOSV refresh
  42. 2026-05-26 13:42 UTCEPSS rescore
  43. 2026-05-26 13:42 UTCEPSS rescore
  44. 2026-05-26 07:17 UTCEPSS rescore
  45. 2026-05-26 07:17 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCRedTeamPentesting/CVE-2020-13935
    First seen Nov 2, 2020

    Exploit for WebSocket Vulnerability in Apache Tomcat

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2020-13935?
CVE-2020-13935 is a critical vulnerability published on July 14, 2020. 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…
When was CVE-2020-13935 disclosed?
CVE-2020-13935 was first published in the National Vulnerability Database on July 14, 2020, with the most recent update on August 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-13935 actively exploited?
CVE-2020-13935 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 87% probability of exploitation in the next 30 days, which ranks it in the top 0.3% of all scored CVEs.
What is the CVSS score of CVE-2020-13935?
CVE-2020-13935 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
How do I remediate CVE-2020-13935?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-13935, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2020-13935

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