CVE-2020-1938 CISA KEV critical CVSS 9.8

[KEV] Privilege Escalation in org.apache.tomcat.embed:tomcat-embed-core (CVE-2020-1938)

Summary

Vulnerability in org.apache.tomcat.embed:tomcat-embed-core (CVE-2020-1938). Successful exploitation can lead to full system takeover. Listed in CISA KEV — actively exploited. Mitigation: upgrade to 7.0.100 or later.

Original description

The description as published by the source.

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 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 configuratio…

Source: CISA Known Exploited Vulnerabilities NVD GitHub Advisory CISA KEV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2020-1938 has been found in org.apache.tomcat.embed:tomcat-embed-core.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
Note: CISA has officially confirmed this is actively exploited in the wild. Treat it with elevated urgency.
What to do: upgrade org.apache.tomcat.embed:tomcat-embed-core to 7.0.100 or later.
If unsure, ask your IT team or search "org.apache.tomcat.embed:tomcat-embed-core CVE-2020-1938" on the vendor's site.

CVE-2020-1938 (org.apache.tomcat.embed:tomcat-embed-core) — CWE-269 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 7.0.100 — apply immediately
Listed in CISA KEV — actively exploited, treat as top priority.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-269) exists in org.apache.tomcat.embed:tomcat-embed-core.

📍 Affected scope

Check the vendor advisory for the affected versions of org.apache.tomcat.embed:tomcat-embed-core.

🔥 Severity

Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover. Listed in CISA KEV — actively exploited in the wild, treat as top priority.

🔧 How to fix

Update to 7.0.100.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで org.apache.tomcat.embed:tomcat-embed-core を使っているサービスとバージョンを洗い出す。
2
Consider incident declaration escalate
```
Notify SOC / on-call
```
CISA KEV登録済 = 実環境で悪用が観測されている。侵入の兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。
3
Apply patch patch
```
Upgrade org.apache.tomcat.embed:tomcat-embed-core to 7.0.100
```
ステージング環境で 7.0.100 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
4
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Maven org.apache.tomcat.embed:tomcat-embed-core

[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.0.100"}]}]

Bitnami tomcat

[{"type":"SEMVER","events":[{"introduced":"7.0.0"},{"fixed":"7.0.100"},{"introduced":"8.5.0"},{"fixed":"8.5.51"},{"introduced":"9.0.0"},{"fixed":"9.0.31"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Debian DEBIAN-CVE-2020-1938 tomcat9 Fixed in: 9.0.31-1
Ubuntu UBUNTU-CVE-2020-1938 tomcat7