Information Disclosure in Apache Tomcat (CVE-2020-17527)
Summary
Vulnerability in Apache Tomcat (CVE-2020-17527). Confidential information can be exposed externally.
Original description
The description as published by the source.
While investigating bug 64830 it was discovered that Apache Tomcat 9.0.0 through 9.0.39 and 8.5.0 to 8.5.59 could re-use an HTTP request header value from the previous stream received on an HTTP/2 connection for the request associated with the subsequent stream. While this would most likely lead to an error and the closure of the HTTP/2 connection, it is possible that information could leak between requests.
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
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-2020-17527 has been found in Apache Tomcat.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Apache Tomcat CVE-2020-17527" on the vendor's site.
CVE-2020-17527 (Apache Tomcat) — CWE-200 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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.
Information disclosure (CWE-200) exists in Apache Tomcat.
Check the vendor advisory for the affected versions of Apache Tomcat.
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Tomcat' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Tomcat' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Tomcatを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-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
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2020-17527 tomcat9 Fixed in: 9.0.16-3ubuntu0.18.04.2
References
- advisory openwall.com
- advisory lists.apache.org
- advisory lists.debian.org
- advisory security.gentoo.org
- advisory security.netapp.com
- advisory debian.org
- advisory oracle.com
- advisory oracle.com
- advisory oracle.com
- advisory oracle.com
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web lists.apache.org
- web nvd.nist.gov