Application Policy Infrastructure ControllerApplication · Cisco
CVE-2021-1582
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 · uneditedA vulnerability in the web UI of Cisco Application Policy Infrastructure Controller (APIC) or Cisco Cloud APIC could allow an authenticated, remote attacker to perform a stored cross-site scripting attack on an affected system. This vulnerability is due to improper input validation in the web UI. An authenticated attacker could exploit this vulnerability by sending malicious input to the web UI. A successful exploit could allow the attacker to execute arbitrary script code in the context of the web-based interface or access sensitive, browser-based information.
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 analysisUntrusted input is placed into a web page without being neutralised, so an attacker's markup or script executes in another user's browser. That can hijack sessions, capture keystrokes, or silently perform actions as the victim. Fixing it properly means context-aware output encoding everywhere data meets HTML, backed by a content-security policy as a second line of defence.
General guidance for the cross-site scripting (xss) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
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
Application Policy Infrastructure ControllerApplication
< 3.2\(10f\)>= 4.0, < 4.2\(7i\)>= 5.0, < 5.2\(2f\)
Cloud Application Policy Infrastructure ControllerApplication
< 3.2\(10f\)>= 4.0, < 4.2\(7i\)>= 5.0, < 5.2\(1h\)CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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 · scoped3.24.25.2
Application Policy Infrastructure Controller: 3.2(10f), 4.2(7i), or 5.2(2f) or later; Cloud Application Policy Infrastructure Controller: 3.2(10f), 4.2(7i), or 5.2(1h) or later
- 1. Identify the currently installed version of Cisco Application Policy Infrastructure Controller (APIC) or Cisco Cloud APIC via the web UI or CLI
- 2. For Application Policy Infrastructure Controller: If running < 3.2, upgrade to 3.2(10f) or later; if running 4.0-4.2.x, upgrade to 4.2(7i) or later; if running 5.0-5.2.x, upgrade to 5.2(2f) or later
- 3. For Cloud Application Policy Infrastructure Controller: If running < 3.2, upgrade to 3.2(10f) or later; if running 4.0-4.2.x, upgrade to 4.2(7i) or later; if running 5.0-5.2.x, upgrade to 5.2(1h) or later
- 4. Obtain the upgrade from Cisco via the Cisco Software Checker or direct download from Cisco.com (requires valid service contract)
- 5. Follow Cisco's standard APIC upgrade procedure documented in the installation and upgrade guide
- 6. After upgrade, verify the new version is running and test that the web UI functions normally
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1582 — 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-2021-1582 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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