CVE intelligence and bounded remediation
CVE-2020-1935 — Apache Tomcat security vulnerability
In Apache Tomcat 9.0.0.M1 to 9.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99 the HTTP header parsing code used an approach to end-of-line parsing that allowed some invalid HTTP headers to be parsed as valid. This led to a possibility of HTTP Request Smuggling if Tomcat was located behind a reverse proxy that incorrectly handled the invalid Transfer-Encoding header in a particular manner. Such a reverse proxy is considered unlikely.
- Severity
- Medium
- CVSS
- 5.8 (2.0)
- Published
- 2020-02-24
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-444
Affected products
- apache / tomcat
- apache / tomcat / 9.0.0
Showing 2 representative product identities from 60 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.
Matched remediation archetype
HTTP request smuggling and message-boundary ambiguity
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Check exposure
- Inventory every proxy, CDN, gateway, load balancer, service mesh, and application server hop on affected request paths.
- Compare documented parsing and normalization behavior for message length, transfer coding, duplicate headers, and protocol translation.
- Identify connection reuse and which downstream services trust headers added by intermediaries.
Remediate safely
- Update affected intermediaries and origin servers and align them on a single standards-compliant request framing policy.
- Reject ambiguous length, transfer-coding, duplicate, malformed, and unsupported framing before forwarding.
- Normalize or remove hop-by-hop and identity headers at one controlled boundary and add multi-hop regression tests.
Authoritative sources
Complete CVE record and remediation plan
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