CVE-2020-13935

CRITICALNVD 7.59.0
EchelonGraph scoreHIGH confidence

“▲” beside the score: it is higher than NVD's CVSS score.

Score elevated to 9.0 because EPSS predicted 87% probability of exploitation within the next 30 days (99th percentile of EPSS-scored CVEs) when EchelonGraph scored this CVE. NVD baseline CVSS 7.5 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction (continuous uplift above 30%)
Sources: EPSS, NVD CVSS v3
Trending — 3 sources updated this weekElevated

Also known asEUVD-2022-1098 (ENISA EUVD) · GHSA-m7jv-hq7h-mq7c (GitHub Security Advisories)Source: ENISA EUVD

9.0EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • 103 internet-facing services (distinct ip:port) on record running an affected version — derived from Shodan data (© Shodan); a patched service can stay counted while its port stays open
  • High exploitation likelihood — EPSS 87%
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 87%CVSS: 7.5Exploit: Public PoCExposed services: 103

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.

Internet exposure · derived from Shodan data

103 internet-facing services (distinct ip:port) on record running a version that maps to CVE-2020-13935, in our KEV-Exposure radar’s Shodan-derived sample.

across 26 countries (China, United States, Germany, Brazil, Korea, Republic of)top: tomcat
See the KEV-Exposure radar →Derived from Shodan data. Shodan data is owned by Shodan, which holds its copyright (© Shodan). EchelonGraph claims no ownership of it or copyright in it. Aggregate, host-redacted.

How it counts: every 12 hours, when Shodan query credits allow, the radar runs one Shodan query per tracked product, reads up to 100 ip:port services per query, and keeps a service when its banner version matches a CISA-KEV or high-EPSS CVE; a service is dropped when neither a search nor a Shodan InternetDB port re-check has refreshed it for 21 days. A re-check that finds the port still listed by Shodan InternetDB refreshes the service without re-reading the banner, so a patched service can stay counted while its port stays open. A count is a banner-version inference over a sample, not an exploit test and not an internet-wide census, and the unit is a service, not a machine: a machine answering on two ports counts twice.

CVSS v3
7.5
EG Score
9.0CRITICALhigh confidence
EG Risk
83
EG Risk 83/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation87% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
87%
EPSS %ILE
99th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.0): severity, escalated by confirmed exploitation. This CVE's 9.0 is EPSS's lift toward 9.0 from its impact severity (EG Severity, CVSS 7.5 HIGH): a likelihood of exploitation, not impact.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
EG Likelihood
87% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 14, 2020

Last Modified

October 8, 2026

Patch Availability(11)

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

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 rangeFix by version rangeDependents
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-M6
  • 7.0.27 up to 7.0.105: fixed in 7.0.105
  • 8.5.0 up to 8.5.57: fixed in 8.5.57
  • 9.0.0.M1 up to 9.0.37: fixed in 9.0.37
  • 10.0.0-M1 up to 10.0.0-M7: fixed in 10.0.0-M7
—
org.apache.tomcat:tomcat7.0.100 ... 7.0.99 (47 versions)
  • 10.0.0-M1 up to 10.0.0-M7: fixed in 10.0.0-M7
  • 9.0.0.M1 up to 9.0.37: fixed in 9.0.37
  • 8.5.0 up to 8.5.57: fixed in 8.5.57
  • 7.0.27 up to 7.0.105: fixed in 7.0.105
—
org.apache.tomcat:tomcat-websocket8.5.0 ... 8.5.9 (45 versions)
  • 10.0.0-M1 up to 10.0.0-M7: fixed in 10.0.0-M7
  • 9.0.0.M1 up to 9.0.37: fixed in 9.0.37
  • 8.5.0 up to 8.5.57: fixed in 8.5.57
  • 7.0.27 up to 7.0.105: fixed in 7.0.105
—
Debian:10(1)
PackageVulnerable rangeFix by version rangeDependents
tomcat99.0.16-4 ... 9.0.31-1~deb10u1 (7 versions)
  • every version up to 9.0.31-1~deb10u2: fixed in 9.0.31-1~deb10u2
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
tomcat9—
  • every version up to 9.0.37-1: fixed in 9.0.37-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
tomcat9—
  • every version up to 9.0.37-1: fixed in 9.0.37-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
tomcat9—
  • every version up to 9.0.37-1: fixed in 9.0.37-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
tomcat9—
  • every version up to 9.0.37-1: fixed in 9.0.37-1
—
Debian:9(1)
PackageVulnerable rangeFix by version rangeDependents
tomcat88.5.14-1 ... 8.5.54-0+deb9u2 (39 versions)
  • every version up to 8.5.54-0+deb9u3: fixed in 8.5.54-0+deb9u3
—

Weakness Classification(1)

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

Additional Vendor Advisories

(6)

Data Freshness Timeline

(refreshed 18× in last 7d / 50× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 94 of 126 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 6 repeat rows among the latest 100 are merged into the row they repeat. The 32 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-31 16:55 UTCEG score recompute
  2. 2026-10-31 16:55 UTCVendor advisory
  3. 2026-10-31 16:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  4. 2026-10-30 14:49 UTCEG score recompute
  5. 2026-10-30 14:49 UTCVendor advisory
  6. 2026-10-29 16:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  7. 2026-10-29 12:56 UTCEG score recompute
  8. 2026-10-29 12:56 UTCVendor advisory
  9. 2026-10-28 11:04 UTCEG score recompute
  10. 2026-10-28 11:04 UTCVendor advisory
  11. 2026-10-27 16:27 UTCEPSS rescoreEPSS 87% · 99th percentile
  12. 2026-10-27 08:24 UTCEG score recompute
  13. 2026-10-27 08:24 UTCVendor advisory
  14. 2026-10-26 04:20 UTCVendor advisory
  15. 2026-10-25 18:51 UTCEG score recompute
  16. 2026-10-25 16:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  17. 2026-10-25 02:25 UTCEG score recompute
  18. 2026-10-25 02:25 UTCVendor advisory
  19. 2026-10-24 00:34 UTCEG score recompute
  20. 2026-10-24 00:34 UTCVendor advisory
  21. 2026-10-23 16:27 UTCEPSS rescoreEPSS 87% · 99th percentile
  22. 2026-10-22 22:41 UTCEG score recompute
  23. 2026-10-22 22:41 UTCVendor advisory
  24. 2026-10-21 20:43 UTCEG score recompute
  25. 2026-10-21 20:43 UTCVendor advisory
Show 69 more
  1. 2026-10-21 16:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  2. 2026-10-20 18:50 UTCEG score recompute
  3. 2026-10-20 18:50 UTCVendor advisory
  4. 2026-10-19 16:55 UTCEG score recompute
  5. 2026-10-19 16:55 UTCVendor advisory
  6. 2026-10-19 16:27 UTCEPSS rescoreEPSS 87% · 99th percentile
  7. 2026-10-18 15:03 UTCVendor advisory
  8. 2026-10-18 09:34 UTCEG score recompute
  9. 2026-10-17 13:10 UTCEG score recompute
  10. 2026-10-17 13:10 UTCVendor advisory
  11. 2026-10-16 11:18 UTCEG score recompute
  12. 2026-10-16 11:18 UTCVendor advisory
  13. 2026-10-15 09:23 UTCEG score recompute
  14. 2026-10-15 09:23 UTCVendor advisory
  15. 2026-10-14 16:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  16. 2026-10-14 05:39 UTCEG score recompute
  17. 2026-10-14 05:39 UTCVendor advisory
  18. 2026-10-13 00:53 UTCVendor advisory
  19. 2026-10-12 19:46 UTCEG score recompute
  20. 2026-10-12 00:09 UTCEG score recompute
  21. 2026-10-08 21:25 UTCEG score recompute
  22. 2026-10-08 21:25 UTCVendor advisory
  23. 2026-10-07 23:43 UTCEPSS rescoreEPSS 87% · 99th percentile
  24. 2026-10-03 14:22 UTCEPSS rescoreEPSS 87% · 99th percentile
  25. 2026-10-02 17:40 UTCOSV refresh
  26. 2026-09-30 15:11 UTCEG score recompute
  27. 2026-09-26 15:54 UTCEPSS rescoreEPSS 87% · 99th percentile
  28. 2026-09-26 00:20 UTCEPSS rescoreEPSS 87% · 99th percentile
  29. 2026-09-24 13:59 UTCEPSS rescoreEPSS 87% · 99th percentile
  30. 2026-09-22 14:43 UTCEPSS rescoreEPSS 87% · 99th percentile
  31. 2026-09-21 20:28 UTCEPSS rescoreEPSS 87% · 99th percentile
  32. 2026-09-19 15:37 UTCEPSS rescoreEPSS 87% · 99th percentile
  33. 2026-09-18 19:23 UTCEPSS rescoreEPSS 87% · 99th percentile
  34. 2026-09-16 14:04 UTCEPSS rescoreEPSS 87% · 99th percentile
  35. 2026-09-13 15:13 UTCOSV refresh
  36. 2026-09-12 14:56 UTCEPSS rescoreEPSS 87% · 99th percentile
  37. 2026-09-06 13:44 UTCEPSS rescoreEPSS 87% · 99th percentile
  38. 2026-09-05 15:24 UTCEPSS rescoreEPSS 87% · 99th percentile
  39. 2026-09-04 13:56 UTCEPSS rescoreEPSS 87% · 99th percentile
  40. 2026-09-04 05:03 UTCEPSS rescoreEPSS 87% · 99th percentile
  41. 2026-09-01 03:32 UTCEPSS rescoreEPSS 87% · 99th percentile
  42. 2026-08-30 19:14 UTCEPSS rescoreEPSS 87% · 99th percentile
  43. 2026-08-28 21:37 UTCEPSS rescoreEPSS 87% · 99th percentile
  44. 2026-08-26 14:42 UTCEPSS rescoreEPSS 87% · 99th percentile
  45. 2026-08-25 16:36 UTCEG score recompute
  46. 2026-08-25 16:36 UTCVendor advisory
  47. 2026-08-20 22:51 UTCEPSS rescoreEPSS 87% · 99th percentile
  48. 2026-08-20 16:01 UTCOSV refresh
  49. 2026-08-16 02:11 UTCEPSS rescoreEPSS 87% · 99th percentile
  50. 2026-08-12 13:47 UTCEPSS rescoreEPSS 87% · 99th percentile
  51. 2026-08-07 16:23 UTCEPSS rescoreEPSS 87% · 99th percentile
  52. 2026-08-05 10:11 UTCOSV refresh
  53. 2026-08-02 02:23 UTCEPSS rescoreEPSS 87% · 99th percentile
  54. 2026-07-30 16:24 UTCEPSS rescoreEPSS 88% · 99th percentile
  55. 2026-07-25 14:14 UTCEPSS rescoreEPSS 88% · 99th percentile
  56. 2026-07-24 14:14 UTCEPSS rescoreEPSS 88% · 99th percentile
  57. 2026-07-23 14:15 UTCEPSS rescoreEPSS 88% · 99th percentile
  58. 2026-07-23 01:49 UTCEG score recompute
  59. 2026-07-22 22:34 UTCEG score recompute
  60. 2026-07-22 14:05 UTCEPSS rescoreEPSS 88% · 99th percentile
  61. 2026-07-20 17:04 UTCEPSS rescoreEPSS 88% · 99th percentile
  62. 2026-07-19 09:22 UTCOSV refresh
  63. 2026-07-15 16:55 UTCEPSS rescoreEPSS 88% · 99th percentile
  64. 2026-07-13 06:10 UTCEPSS rescoreEPSS 88% · 99th percentile
  65. 2026-07-06 02:20 UTCEPSS rescoreEPSS 88% · 99th percentile
  66. 2026-07-01 15:03 UTCEPSS rescoreEPSS 88% · 99th percentile
  67. 2026-07-01 15:01 UTCOSV refresh
  68. 2026-06-25 13:47 UTCEPSS rescoreEPSS 88% · 99th percentile
  69. 2026-06-23 21:31 UTCEPSS rescoreEPSS 88% · 99th percentile

Publicly available exploits

(1 reference)

Public exploit code is referenced for this CVE (1 GitHub PoC). Defenders should treat patch urgency accordingly.

  • GitHub PoCRedTeamPentesting/CVE-2020-13935
    Published Nov 2, 2020

    Exploit for WebSocket Vulnerability in Apache Tomcat

    Open source ↗

Frequently asked(5)

What is CVE-2020-13935?
CVE-2020-13935 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2020-13935 published?
The CVE record for CVE-2020-13935 was published on July 14, 2020. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 8, 2026; the record at its source may have been updated since.
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 (99th percentile of EPSS-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 + FIRST EPSS into a combined EG score of 9.0 (CRITICAL).
How do I remediate CVE-2020-13935?
A fix for CVE-2020-13935 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2020-13935 are linked in the Vendor Advisories panel on this page.

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