CVE-2021-31923
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 · uneditedPing Identity PingAccess before 5.3.3 allows HTTP request smuggling via header manipulation.
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 confidencePing Identity PingAccess before 5.3.3 is vulnerable to HTTP request smuggling through header manipulation. This allows attackers to craft ambiguous HTTP requests that the proxy interprets differently than backend servers, potentially bypassing security controls, performing cache poisoning, or gaining unauthorized access.
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< 5.3.3CVSS 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
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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 PingAccess installation and versionCheck the PingAccess version by reviewing the $PINGACCESS_HOME/lib/pingaccess-*.jar file name, or run: cd $PINGACCESS_HOME && ls -la lib/pingaccess-*.jar. The version appears in the filename (e.g., pingaccess-5.3.2.jar).Affected if The installed version number is lower than 5.3.3 (e.g., 5.3.2, 5.3.1, 5.3.0, etc.)
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Confirm PingAccess admin console accessLog into the PingAccess admin console at https://localhost:9000/pa/oidc/callback or the configured admin URL, then navigate to System -> Configuration -> Server Settings to view the exact version displayed.Affected if The console reports a version below 5.3.3
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Verify HTTP proxy/listener is enabledIn PingAccess admin console, check under Network -> Listeners or the proxy configuration section. Confirm whether HTTP(S) listeners are configured and active for processing inbound requests.Affected if An HTTP or HTTPS listener is active and processing external traffic, enabling the request smuggling attack vector
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Check network exposure of PingAccessReview firewall rules, security groups, or network ACLs to determine if the PingAccess HTTP listeners are accessible from untrusted networks (e.g., the internet or DMZ). Use netstat or ss to list listening ports (typically 8080, 8443, 9000, etc.).Affected if The PingAccess proxy ports are exposed to untrusted networks, making the request smuggling flaw reachable by external attackers
You are affected if PingAccess version is below 5.3.3 AND the HTTP proxy functionality is enabled and accessible to potential 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.
dbcve · scoped5.3.3
Upgrade PingAccess to version 5.3.3 or later to obtain the vendor patch for this vulnerability.
PingAccess 5.3.3
- Plan and schedule the upgrade during a maintenance window
- Backup the current PingAccess configuration and data
- Download PingAccess version 5.3.3 from the Ping Identity download portal or official source
- Stop the PingAccess service before upgrade
- Install PingAccess 5.3.3 following the standard upgrade procedure
- Verify the installation completed successfully
- Start the PingAccess service
- Test that applications protected by PingAccess are accessible and functioning correctly
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-31923 — 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-2021-31923 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
- No spam, self-promotion, credentials, or personal data