CriticalCVE-2021-22506

    Micro Focus Access Manager Information Leakage Vulnerability (CVE-2021-22506)

    Published In CISA KEV since Sources: CVE.org

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    What is affected, what to do

    Advance configuration exposing Information Leakage vulnerability in Micro Focus Access Manager product, affects all versions prior to version 5.0. The vulnerability could cause information leakage.

    The vulnerability is being actively exploited; treat it as a priority. Update access_manager to version 5.0. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Access Manager. eq All version prior version 5.0...All version prior version 5.0.

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org

    25.7 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 98.0

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    214.30 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

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    actively exploited
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.5
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

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    25.7 %
    Elevated — model estimates 10-50% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

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    98.0
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

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    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CISA assessment (SSVC)
    Exploitation: active · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 6 February 2025

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The flaw is network-reachable without authentication and has low attack complexity. Its value to attackers is assertion theft: a crafted AuthnRequest makes the IdP deliver a SAML assertion to an attacker-controlled endpoint. That enables session hijacking across federated applications, typically as part of phishing campaigns against organisations using centralised SSO. Exploitation likelihood is very high, and CISA does not flag known ransomware use. Treat internet-facing Access Manager deployments below 5.0 that act as the primary IdP for critical applications as high-to-critical and fix them urgently. Internal-only instances with strict ACS validation can follow the regular patch cycle.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory: Find every Micro Focus (NetIQ) Access Manager component: Identity Server, Access Gateway and Administration Console. Any version below 5.0 is affected.
      • Upgrade to Access Manager 5.0: This release contains the fix. Check the vendor advisory for the exact build and the cluster upgrade order. Roll the upgrade node by node so authentication stays available.
      • If you cannot upgrade immediately: In the Identity Server SAML 2.0 settings, check each trusted service provider for whether the ACS URL is taken from the AuthnRequest. If it is, restrict it to the endpoints declared in the SP metadata only.
      • Invalidate sessions: If you suspect exploitation, terminate active IdP sessions and sessions at federated SPs. Force re-authentication for users with privileged access to federated applications.
      • Reduce exposure: Make sure the Administration Console is not internet-reachable. Restrict access to a management network or jump host.

    2. Runbook step 2

      Mitigation layers

      • Configuration (IdP): Require signed AuthnRequests from all SPs. Reject unsigned requests that carry a non-registered ACS URL. Remove stale SP trusts.
      • WAF/reverse proxy in front of the Identity Server: Inspect requests to /nidp/saml2/sso and decode SAMLRequest (Redirect binding: base64 + deflate; POST binding: base64). Block or alert when AssertionConsumerServiceURL falls outside an allowlist of registered SP domains.
      • Network segmentation: Separate the Identity Server and Administration Console into distinct zones. Expose only the Access Gateway/DMZ tier to the internet.
      • IAM/least privilege: Keep assertion lifetimes short (tight NotOnOrAfter). Enforce a strict Audience Restriction to the SP entity ID. Encrypt assertions for high-value SPs so leaked assertions are harder to reuse.
      • Service-provider side: Ensure SPs validate InResponseTo, Recipient and Destination, and keep an assertion-ID replay cache. This limits the value of intercepted assertions.

    3. Runbook step 3

      Detection rules

      • Identity Server logs (catalina.out / NIDP logs): Hunt for AuthnRequests whose ACS URL differs from the registered metadata or points to external or unknown domains. SPL example: index=nam sourcetype=nidp "AssertionConsumerServiceURL" NOT AssertionConsumerServiceURL IN ("https://app1.example.com/*","https://app2.example.com/*").
      • Web proxy logs: Look for client POSTs carrying a SAMLResponse form field to non-SP destinations. A Referer from the IdP host followed by a POST to an unknown domain is a strong signal. Sigma shape: cs-method=POST AND cs-referer|contains=<idp-host> AND NOT cs-host IN <sp-allowlist>.
      • Web server/WAF access logs: Watch for bursts of /nidp/saml2/sso requests with unusually long or varying SAMLRequest values from single sources. This points to scanning or phishing campaigns using crafted links.
      • Zeek/Suricata: Correlate new TLS SNI destinations contacted right after IdP sessions (ssl.log time-proximity joins). Also flag DNS lookups for newly registered domains that look like your IdP or brand.
      • SP sign-in logs: Flag valid-assertion logins from IPs or geolocations that don't match the same user's preceding IdP authentication. This indicates a stolen assertion being replayed.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Advance configuration exposing Information Leakage vulnerability in Micro Focus Access Manager product, affects all versions prior to version 5.0. The vulnerability could cause information leakage.

    Source: NVD (NIST), cvelistv5, CISA KEV Catalog

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    —Access Manager.
    • All version prior version 5.0.
    • —
    microfocusaccess_manager
    • < 5.0
    • 5.0

    Vendors and products

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited

    References & sources

    • microfocus.comdocumentation/access-manager/5.0/accessmanager50-release-notes/…x_refsource_MISC, Release notes
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22506government-resource, US government resource
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