CVE-2020-1938
When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising. In Apache Tomcat 9.0.0.M1 to 9.0.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99, Tomcat shipped with an AJP Connector enabled by default that listened on all configured IP addresses. It was expected (and recommended in the security guide) that this Connector would be disabled if not required. This vulnerability report identified a mechanism that allowed: - returning arbitrary files from anywhere in the web application - processing any file in the web application as a JSP Further, if the web application allowed file upload and stored those files within the web application (or the attacker was able to control the content of the web application by some other means) then this, along with the ability to process a file as a JSP, made remote code execution possible. It is important to note that mitigation is only required if an AJP port is accessible to untrusted users. Users wishing to take a defence-in-depth approach and block the vector that permits returning arbitrary files and execution as JSP may upgrade to Apache Tomcat 9.0.31, 8.5.51 or 7.0.100 or later. A number of changes were made to the default AJP Connector configuration in 9.0.31 to harden the default configuration. It is likely that users upgrading to 9.0.31, 8.5.51 or 7.0.100 or later will need to make small changes to their configurations.
- CVSS
- 9.8Criticalscored by CISA
- Exploited in the wild
- Yes, in CISA KEV since 3 Mar 2022CISA deadline for US federal agencies: 17 Mar 2022public exploit code
- EPSS
- 99.3%chance of exploitation in the next 30 daystop 0.1% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 24 Feb 2020analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
- Exploitable
- At runtime
- Attack vector
- network
- Can a WAF block it?
- Partly. See why
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Apache Apache Tomcat | Apache Tomcat 9.0.0.M1 to 9.0.0.308.5.0 to 8.5.507.0.0 to 7.0.99Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- apache:geode
- apache:tomcat
- fedoraproject:fedora
- oracle:agile_engineering_data_management
- oracle:agile_product_lifecycle_management
- oracle:communications_element_manager
- oracle:communications_instant_messaging_server
- oracle:health_sciences_empirica_inspections
- oracle:health_sciences_empirica_signal
- oracle:hospitality_guest_access
- oracle:instantis_enterprisetrack
- oracle:mysql_enterprise_monitor
- oracle:siebel_ui_framework
- oracle:transportation_management
- oracle:workload_manager
- debian:debian_linux
- opensuse:leap
- blackberry:good_control
- blackberry:workspaces_server
- netapp:data_availability_services
- netapp:oncommand_system_manager
Fix and mitigation
WAF and other mitigations
Can a WAF block it? Partly. The bug can be reached over the network, so generic WAF rules may stop some attacks. Its weakness type is unknown, so we cannot be more precise.
Also consider: patch
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 3 Mar 2022.
- CISA due date
- 17 Mar 2022, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- Yes: 2 on Exploit-DB · 1 Metasploit module · 40 GitHub proofs of concept · 1 Nuclei template
- CISA SSVC
- exploitation active, automatable yes, technical impact totalAssessed by CISA 6 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Exploit-DB
- Apache Tomcat - AJP 'Ghostcat' File Read/Inclusion (Metasploit)webapps, 13 Nov 2020, verified by Exploit-DB
- Apache Tomcat - AJP 'Ghostcat File Read/Inclusionwebapps, 20 Feb 2020
Metasploit
- auxiliary/admin/http/tomcat_ghostcatauxiliary, rank normal
Nuclei
- Ghostcat - Apache Tomcat - AJP File Read/Inclusion Vulnerabilitydetection template, critical
GitHub proofs of concept
- 00theway/Ghostcat-CNVD-2020-10487422 stars
- lizhianyuguangming/TomcatScanPro297 stars
- bkfish/CNVD-2020-10487-Tomcat-Ajp-lfi-Scanner294 stars
- tpt11fb/AttackTomcat258 stars
and 36 more repositories
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 20 Feb 2020First public exploit or proof of concept
- 24 Feb 2020Published5 days later
- 3 Mar 2022Added to CISA KEV (exploited in the wild)737 days (about 2 years) later
- 17 Mar 2022CISA remediation due date (US federal agencies)14 days later
- 6 Feb 2025CISA SSVC assessment: exploitation active1,058 days (about 3 years) later
- 21 Oct 2025CVE record last updated257 days (about 9 months) later
- 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | NetworkReachable over the internet or any routable network. | Reachable over the internet or any routable network. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2020-1938 being exploited?
Yes. CVE-2020-1938 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2020-1938?
CVE-2020-1938 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2020-1938?
Yes. A fix has been recorded for CVE-2020-1938. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2020-1938 affect?
CVE-2020-1938 affects apache:geode, apache:tomcat, fedoraproject:fedora, oracle:agile_engineering_data_management, and 17 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
50 references in the CVE record, grouped by the tags the record gives them.
Advisories (8)
- lists.opensuse.org /opensuse-security-announce/2020-03/msg00025.html
- security.gentoo.org /glsa/202003-43
- lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/2XFLQB3O5QVP4Z
- lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/L46WJIV6UV3FWA
- lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/K3IPNHCKFVUKSH
- lists.opensuse.org /opensuse-security-announce/2020-05/msg00002.html
Show 2 more
- debian.org /security/2020/dsa-4673
- debian.org /security/2020/dsa-4680
Other links (42)
- lists.apache.org /thread.html/r7c6f492fbd39af34a68681dbbba0468490ff1a97a1bd79c6a53610ef%40%3Canno
- lists.apache.org /thread.html/r856cdd87eda7af40b50278d6de80ee4b42d63adeb433a34a7bdaf9db%40%3Cnoti
- lists.apache.org /thread.html/r75113652e46c4dee687236510649acfb70d2c63e074152049c3f399d%40%3Cnoti
- lists.apache.org /thread.html/rd0774c95699d5aeb5e16e9a600fb2ea296e81175e30a62094e27e3e7%40%3Ccomm
- lists.apache.org /thread.html/r74328b178f9f37fe759dffbc9c1f2793e66d79d7a8a20d3836551794%40%3Cnoti
- lists.apache.org /thread.html/rce2af55f6e144ffcdc025f997eddceb315dfbc0b230e3d750a7f7425%40%3Cnoti
Show 36 more
- lists.apache.org /thread.html/rad36ec6a1ffc9e43266b030c22ceeea569243555d34fb4187ff08522%40%3Cnoti
- lists.apache.org /thread.html/rb2fc890bef23cbc7f343900005fe1edd3b091cf18dada455580258f9%40%3Cuser
- lists.apache.org /thread.html/r38a5b7943b9a62ecb853acc22ef08ff586a7b3c66e08f949f0396ab1%40%3Cuser
- lists.apache.org /thread.html/r17aaa3a05b5b7fe9075613dd0c681efa60a4f8c8fbad152c61371b6e%40%3Cuser
- lists.apache.org /thread.html/rd50baccd1bbb96c2327d5a8caa25a49692b3d68d96915bd1cfbb9f8b%40%3Cuser
- lists.apache.org /thread.html/r4afa11e0464408e68f0e9560e90b185749363a66398b1491254f7864%40%3Cuser
- lists.apache.org /thread.html/r772335e6851ad33ddb076218fa4ff70de1bf398d5b43e2ddf0130e5d%40%3Cdev.
- lists.debian.org /debian-lts-announce/2020/03/msg00006.html
- lists.apache.org /thread.html/re5eecbe5bf967439bafeeaa85987b3a43f0e6efe06b6976ee768cde2%40%3Cuser
- lists.apache.org /thread.html/r5e2f1201b92ee05a0527cfc076a81ea0c270be299b87895c0ddbe02b%40%3Cuser
- lists.apache.org /thread.html/r549b43509e387a42656f0641fa311bf27c127c244fe02007d5b8d6f6%40%3Cdev.
- lists.apache.org /thread.html/r61f280a76902b594692f0b24a1dbf647bb5a4c197b9395e9a6796e7c%40%3Cuser
- lists.apache.org /thread.html/r4f86cb260196e5cfcbbe782822c225ddcc70f54560f14a8f11c6926f%40%3Cuser
- lists.apache.org /thread.html/r9f119d9ce9239114022e13dbfe385b3de7c972f24f05d6dbd35c1a2f%40%3Cuser
- lists.apache.org /thread.html/r089dc67c0358a1556dd279c762c74f32d7a254a54836b7ee2d839d8e%40%3Cdev.
- lists.apache.org /thread.html/rbdb1d2b651a3728f0ceba9e0853575b6f90296a94a71836a15f7364a%40%3Cdev.
- lists.apache.org /thread.html/rc068e824654c4b8bd4f2490bec869e29edbfcd5dfe02d47cbf7433b2%40%3Cdev.
- lists.apache.org /thread.html/rf26663f42e7f1a1d1cac732469fb5e92c89908a48b61ec546dbb79ca%40%3Cbugs
- lists.apache.org /thread.html/rcd5cd301e9e7e39f939baf2f5d58704750be07a5e2d3393e40ca7194%40%3Ccomm
- lists.apache.org /thread.html/rf992c5adf376294af31378a70aa8a158388a41d7039668821be28df3%40%3Ccomm
- lists.apache.org /thread.html/r6a5633cad1b560a1e51f5b425f02918bdf30e090fdf18c5f7c2617eb%40%3Ccomm
- lists.apache.org /thread.html/r43faacf64570b1d9a4bada407a5af3b2738b0c007b905f1b6b608c65%40%3Cuser
- lists.debian.org /debian-lts-announce/2020/05/msg00026.html
- lists.apache.org /thread.html/rb1c0fb105ce2b93b7ec6fc1b77dd208022621a91c12d1f580813cfed%40%3Cdev.
- lists.apache.org /thread.html/ra7092f7492569b39b04ec0decf52628ba86c51f15efb38f5853e2760%40%3Cnoti
- lists.apache.org /thread.html/r8f7484589454638af527182ae55ef5b628ba00c05c5b11887c922fb1%40%3Cnoti
- oracle.com /security-alerts/cpujul2020.html
- security.netapp.com /advisory/ntap-20200226-0002/
- support.blackberry.com /kb/articleDetail?articleNumber=000062739
- lists.apache.org /thread.html/r92d78655c068d0bc991d1edbdfb24f9c5134603e647cade1113d4e0a%40%3Cuser
- lists.apache.org /thread.html/rf1bbc0ea4a9f014cf94df9a12a6477d24a27f52741dbc87f2fd52ff2%40%3Cissu
- oracle.com /security-alerts/cpuoct2020.html
- lists.apache.org /thread.html/r57f5e4ced436ace518a9e222fabe27fb785f09f5bf974814cc48ca97%40%3Ccomm
- lists.apache.org /thread.html/r47caef01f663106c2bb81d116b8380d62beac9e543dd3f3bc2c2beda%40%3Ccomm
- oracle.com /security-alerts/cpujan2021.html
- lists.apache.org /thread.html/r90890afea72a9571d666820b2fe5942a0a5f86be406fa31da3dd0922%40%3Canno
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Exploit-DB: published exploits
- Metasploit Framework: exploit and scanner modules
- Nuclei templates: detection templates
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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