CVE-2020-13935: 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…
Noroxi assessment
Priority: Plan (action score 56/100)
- A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 86.6% (FIRST EPSS); higher than 99.7% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: tomcat9 (Debian:10) 9.0.31-1~deb10u2; tomcat9 (Debian:12) 9.0.37-1; tomcat8 (Debian:9) 8.5.54-0+deb9u3.
- Mentioned 4 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Add it to your regular patch cycle. Upgrade to tomcat9 (Debian:10) 9.0.31-1~deb10u2; tomcat9 (Debian:12) 9.0.37-1; tomcat8 (Debian:9) 8.5.54-0+deb9u3 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- BDU:2020-04938
- GHSA-m7jv-hq7h-mq7c
- DLA-2286-1
- DSA-4727-1
- openSUSE-SU-2020:1102-1
- openSUSE-SU-2020:1111-1
- openSUSE-SU-2024:12103-1
- RHSA-2020:3303
- RHSA-2020:3306
- RHSA-2020:3383
- RHSA-2020:4004
- RHSA-2022:5459
- RHSA-2022:5460
- SUSE-SU-2020:2037-1
- SUSE-SU-2020:2045-1
- SUSE-SU-2020:2046-1
- SUSE-SU-2020:2047-1
- SUSE-SU-2020:2611-1
- SUSE-SU-2026:1058-1
- Published
- Jul 14, 2020
- Updated
- Oct 8, 2026
- EPSS
- 86.6% · 99th percentile
- CWE
- CWE-835
Report tools
Action score
56
Add it to your regular patch cycle.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 26 / 30 · 86.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- Proof of concept exists, no weaponized module
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Is your version affected? Check itNoroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| apache | tomcat | cpe:2.3:a:apache:tomcat |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netapp | oncommand system manager | cpe:2.3:a:netapp:oncommand_system_manager |
| opensuse | leap | cpe:2.3:o:opensuse:leap |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| mcafee | epolicy orchestrator | cpe:2.3:a:mcafee:epolicy_orchestrator |
| oracle | agile engineering data management | cpe:2.3:a:oracle:agile_engineering_data_management |
| oracle | agile product lifecycle management | cpe:2.3:a:oracle:agile_product_lifecycle_management |
| oracle | blockchain platform | cpe:2.3:a:oracle:blockchain_platform |
| oracle | commerce guided search | cpe:2.3:a:oracle:commerce_guided_search |
| oracle | communications cloud native core policy | cpe:2.3:a:oracle:communications_cloud_native_core_policy |
| oracle | communications instant messaging server | cpe:2.3:a:oracle:communications_instant_messaging_server |
and 6 more
Versions reported by the vendor
Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.
n/a Apache Tomcat
- 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, 7.0.27 to 7.0.104affected
Affected versions · NVD (20)
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apache tomcat7.0.27 and later · up to 7.0.104 inclusive
- apache tomcat8.5.0 and later · up to 8.5.56 inclusive
- apache tomcat9.0.1 and later · up to 9.0.36 inclusive
- apache tomcat10.0.0
- apache tomcat9.0.0
- canonical ubuntu linux16.04
- canonical ubuntu linux20.04
- debian debian linux10.0
- debian debian linux9.0
- mcafee epolicy orchestrator5.10.0
- mcafee epolicy orchestrator5.9.0
- mcafee epolicy orchestrator5.9.1
- netapp oncommand system manager3.0.0 and later · up to 3.1.3 inclusive
- opensuse leap15.1
- opensuse leap15.2
- oracle agile engineering data management6.2.1.0
- oracle agile product lifecycle management9.3.3
- oracle agile product lifecycle management9.3.5
- oracle agile product lifecycle management9.3.6
- oracle blockchain platformbefore 21.1.2
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:10 | tomcat9 | before 9.0.31-1~deb10u2 | 9.0.31-1~deb10u2 |
| Debian:12 | tomcat9 | before 9.0.37-1 | 9.0.37-1 |
| Debian:9 | tomcat8 | before 8.5.54-0+deb9u3 | 8.5.54-0+deb9u3 |
| Maven | org.apache.tomcat:tomcat | from 10.0.0-M1 · before 10.0.0-M7 | 10.0.0-M7 |
| Maven | org.apache.tomcat:tomcat | from 7.0.27 · before 7.0.105 | 7.0.105 |
| Maven | org.apache.tomcat:tomcat | from 8.5.0 · before 8.5.57 | 8.5.57 |
| Maven | org.apache.tomcat:tomcat | from 9.0.0.M1 · before 9.0.37 | 9.0.37 |
| Maven | org.apache.tomcat:tomcat-websocket | from 10.0.0-M1 · before 10.0.0-M7 | 10.0.0-M7 |
| Maven | org.apache.tomcat:tomcat-websocket | from 7.0.27 · before 7.0.105 | 7.0.105 |
| Maven | org.apache.tomcat:tomcat-websocket | from 8.5.0 · before 8.5.57 | 8.5.57 |
| Maven | org.apache.tomcat:tomcat-websocket | from 9.0.0.M1 · before 9.0.37 | 9.0.37 |
| Maven | org.apache.tomcat.embed:tomcat-embed-websocket | from 10.0.0-M1 · before 10.0.0-M7 | 10.0.0-M7 |
| Maven | org.apache.tomcat.embed:tomcat-embed-websocket | from 7.0.27 · before 7.0.105 | 7.0.105 |
| Maven | org.apache.tomcat.embed:tomcat-embed-websocket | from 8.5.0 · before 8.5.57 | 8.5.57 |
| Maven | org.apache.tomcat.embed:tomcat-embed-websocket | from 9.0.0.M1 · before 9.0.37 | 9.0.37 |
| openSUSE:Leap 15.1 | tomcat | before 9.0.36-lp151.3.27.1 | 9.0.36-lp151.3.27.1 |
| openSUSE:Leap 15.2 | tomcat | before 9.0.36-lp152.2.4.1 | 9.0.36-lp152.2.4.1 |
| openSUSE:Tumbleweed | tomcat | before 9.0.43-8.1 | 9.0.43-8.1 |
| Red Hat:enterprise_linux:7::client | tomcat | before 0:7.0.76-15.el7 | 0:7.0.76-15.el7 |
| Red Hat:enterprise_linux:7::client | tomcat-admin-webapps | before 0:7.0.76-15.el7 | 0:7.0.76-15.el7 |
| Red Hat:enterprise_linux:7::client | tomcat-docs-webapp | before 0:7.0.76-15.el7 | 0:7.0.76-15.el7 |
| Red Hat:enterprise_linux:7::client | tomcat-el-2.2-api | before 0:7.0.76-15.el7 | 0:7.0.76-15.el7 |
| Red Hat:enterprise_linux:7::client | tomcat-javadoc | before 0:7.0.76-15.el7 | 0:7.0.76-15.el7 |
| Red Hat:enterprise_linux:7::client | tomcat-jsp-2.2-api | before 0:7.0.76-15.el7 | 0:7.0.76-15.el7 |
+96
Same product
apache: all recordsOther highest-scoring records for the same primary product.
- CVE-2025-24813Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUTKEV99Now
- CVE-2016-8735Remote code execution is possible with Apache Tomcat before 6.0.48, 7.x before 7.0.73, 8.x before 8.0.39, 8.5.x before 8.5.7, and 9.x…KEV96Now
- CVE-2017-12617When running Apache Tomcat versions 9.0.0.M1 to 9.0.0, 8.5.0 to 8.5.22, 8.0.0.RC1 to 8.0.46 and 7.0.0 to 7.0.81 with HTTP PUTs enabled (e.g.KEV92Now
Published before and after this one in the same product
- ← EarlierCVE-2020-11996Jun 26, 2020 · A specially crafted sequence of HTTP/2 requests sent to Apache Tomcat 10.0.0-M1 to 10.0.0-M5, 9.0.0.M1 to 9.0.35 and 8.5.0 to 8.5.55 could…38Monitor
- ← EarlierCVE-2020-13934Jul 14, 2020 · An h2c direct connection to Apache Tomcat 10.0.0-M1 to 10.0.0-M6, 9.0.0.M5 to 9.0.36 and 8.5.1 to 8.5.56 did not release the HTTP/1.1…49Plan
- Later →CVE-2020-13943Oct 12, 2020 · 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…33Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:tomcat8 | 8.5.54-0+deb9u3 · Debian:9 | Package registry (OSV) |
| debian:tomcat9 | 9.0.37-1 · Debian:12 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat | 10.0.0-M7 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat | 7.0.105 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat | 8.5.57 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat | 9.0.37 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat-websocket | 10.0.0-M7 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat-websocket | 7.0.105 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat-websocket | 8.5.57 | Package registry (OSV) |
| Maven:org.apache.tomcat:tomcat-websocket | 9.0.37 | Package registry (OSV) |
| Maven:org.apache.tomcat.embed:tomcat-embed-websocket | 10.0.0-M7 | Package registry (OSV) |
| Maven:org.apache.tomcat.embed:tomcat-embed-websocket | 7.0.105 | Package registry (OSV) |
| Maven:org.apache.tomcat.embed:tomcat-embed-websocket | 8.5.57 | Package registry (OSV) |
| Maven:org.apache.tomcat.embed:tomcat-embed-websocket | 9.0.37 | Package registry (OSV) |
| opensuse:tomcat | 9.0.36-lp151.3.27.1 · openSUSE:Leap 15.1 | Package registry (OSV) |
| red hat:tomcat7 | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-admin-webapps | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-docs-webapp | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-el-2.2-api | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-javadoc | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-jsp-2.2-api | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-jsvc | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-lib | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-log4j | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-selinux | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-servlet-3.0-api | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| red hat:tomcat7-webapps | 0:7.0.70-41.ep7.el6 · Red Hat:jboss_enterprise_web_server:3.1::el6 | Package registry (OSV) |
| suse:tomcat | 9.0.36-3.45.1 · SUSE:OpenStack Cloud 9 | Package registry (OSV) |
Exploit status
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Nuclei detection template ×1
- Proof-of-concept repository on GitHub ×2
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Nuclei detection template | Nuclei template CVE-2020-13935 | — |
| Proof-of-concept repository on GitHub | stars:167 | 2020-11-02 |
| Proof-of-concept repository on GitHub | stars:0 | 2022-06-02 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- First PoC+110 d
- TodayNov 14, 2026+2313 d
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-21-0331 · Apr 21, 2021(Oracle Güvenlik Uyarısı Yayınladı)
- TR-20-812 · Sep 30, 2020(Apache, Tomcat için Güvenlik Güncellemeleri Yayınladı)
- TR-20-718 · Sep 15, 2020(Red Hat JBoss Enterprise Application Sunucu Güvenlik Güncellemesi)
- TR-20-528 · Jul 16, 2020(Apache, Tomcat için Güvenlik Güncellemeleri Yayınladı)
Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log (2)
- SSVC exploitation— → none
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (16 more)Show less
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00088.html
- kc.mcafee.com/corporate/index?page=content&id=SB10332
- lists.apache.org/thread.html/r4e5d3c09f4dd2923191e972408b40fb8b42dbff0bc7904d44b651e50%40%3Cusers.tomcat.apache.org%3E
- lists.apache.org/thread.html/rd48c72bd3255bda87564d4da3791517c074d94f8a701f93b85752651%40%3Cannounce.tomcat.apache.org%3E
- lists.debian.org/debian-lts-announce/2020/07/msg00017.html
- security.netapp.com/advisory/ntap-20200724-0003/
- usn.ubuntu.com/4448-1/
- usn.ubuntu.com/4596-1/
- www.debian.org/security/2020/dsa-4727
- www.oracle.com//security-alerts/cpujul2021.html
- www.oracle.com/security-alerts/cpuApr2021.html
- www.oracle.com/security-alerts/cpuapr2022.html
- www.oracle.com/security-alerts/cpujan2021.html
- www.oracle.com/security-alerts/cpujan2022.html
- www.oracle.com/security-alerts/cpuoct2020.html
- www.oracle.com/security-alerts/cpuoct2021.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.