CVE-2020-9484 high CVSS 7.0

Unsafe Deserialization in org.apache.tomcat:tomcat-catalina (CVE-2020-9484)

Summary

Vulnerability in org.apache.tomcat:tomcat-catalina (CVE-2020-9484). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 7.0.104 or later.

Original description

The description as published by the source.

When using Apache Tomcat versions 9.0.0 through 9.0.34, 8.5.0 to 8.5.54 and 7.0.0 to 7.0.103 if a) an attacker is able to control the contents and name of a file on the server; and b) the server is configured to use the PersistenceManager with a FileStore; and c) the PersistenceManager is configured with sessionAttributeValueClassNameFilter="null" (the default unless a SecurityManager is used) or a sufficiently lax filter to allow the attacker provided object to be deserialized; and d) the attacker knows the relative file path from the storage location used by FileStore to the file the attacker has control over; then, using a specifically crafted request, the attacker will be able to trigger remote code execution via deserialization of the file under their control. Note that all of conditions a) to d) must be true for the attack to succeed.

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

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-2020-9484 has been found in org.apache.tomcat:tomcat-catalina.
Successful exploitation can lead to full system takeover. CVSS score: 7.0/10.
What to do: upgrade org.apache.tomcat:tomcat-catalina to 7.0.104 or later.
If unsure, ask your IT team or search "org.apache.tomcat:tomcat-catalina CVE-2020-9484" on the vendor's site.

CVE-2020-9484 (org.apache.tomcat:tomcat-catalina) — CWE-502 / CVSS v3 7.0
Attack vector: local / no user interaction
Patched: 7.0.104 — apply immediately
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

Unsafe deserialization (CWE-502) exists in org.apache.tomcat:tomcat-catalina.

📍 Affected scope

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

🔥 Severity

Severity: High (CVSS 7.0/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to 7.0.104.

🛡️ 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:tomcat-catalina を使っているサービスとバージョンを洗い出す。
2
Apply patch patch
```
Upgrade org.apache.tomcat:tomcat-catalina to 7.0.104
```
ステージング環境で 7.0.104 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。
3
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:tomcat-catalina

[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.0.104"}]}]

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

[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0"},{"fixed":"7.0.104"}]}]

Bitnami tomcat

[{"type":"SEMVER","events":[{"introduced":"7.0.0"},{"fixed":"7.0.108"},{"introduced":"8.5.0"},{"fixed":"8.5.63"},{"introduced":"9.0.1"},{"fixed":"9.0.43"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Debian DEBIAN-CVE-2020-9484 tomcat9 Fixed in: 9.0.35-1