CVE-2020-27978
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedShibboleth Identify Provider 3.x before 3.4.6 has a denial of service flaw. A remote unauthenticated attacker can cause a login flow to trigger Java heap exhaustion due to the creation of objects in the Java Servlet container session.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceShibboleth Identity Provider 3.x before 3.4.6 contains a denial of service vulnerability where a remote unauthenticated attacker can cause Java heap exhaustion by triggering the creation of excessive objects in the Java Servlet container session during the login flow.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 3.0.0, < 3.4.6CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed Shibboleth IdP versionCheck the IdP version file typically located at $IDP_HOME/dist/idp.jar or look for version information in the IdP distribution. You can also check the 'idp.version' property in $IDP_HOME/conf/idp.properties if available.Affected if The installed version is 3.0.0 through 3.4.5 (inclusive)
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Verify IdP is exposed to networkConfirm whether the IdP login endpoint (typically at /idp/login or similar path under the web context) is accessible from untrusted networks. Check your servlet container (Tomcat, Jetty, etc.) network binding configuration.Affected if The IdP login endpoint is reachable from remote/untrusted networks and version is vulnerable
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Check servlet container session configurationReview your Java servlet container configuration for session settings. Look for session timeout values and any limits on session objects. The vulnerability stems from excessive session object creation during the login flow.Affected if Session configuration allows long timeouts or permits unlimited session object growth, making the DoS impact more severe
You are affected if your Shibboleth Identity Provider version is 3.0.0 through 3.4.5 and the IdP login interface is network-accessible to remote attackers.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor data3.4.6
Upgrade to Shibboleth IdP version 3.4.6 or later to obtain the vendor patch that addresses the session object creation issue.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-27978 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-27978 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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