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PatchSiren cyber security CVE debrief

CVE-2016-4437 Apache CVE debrief

CVE-2016-4437 is recorded in the supplied corpus as an Apache Shiro code execution vulnerability and is listed by CISA in the Known Exploited Vulnerabilities catalog. CISA’s entry indicates confirmed exploitation and directs defenders to apply updates per vendor instructions. If Apache Shiro is present anywhere in your environment, treat this as a high-priority remediation item.

Vendor
Apache
Product
Shiro
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Security teams, vulnerability management, system administrators, and application owners responsible for systems using Apache Shiro. Incident responders should also care because CISA lists this issue as known exploited.

Technical summary

The supplied records identify the issue as a code execution vulnerability in Apache Shiro. Beyond that high-level classification, the corpus does not provide exploit mechanics, affected versions, or a vendor advisory link. The most actionable authoritative signal in the supplied material is CISA KEV inclusion, which confirms known exploitation and recommends applying vendor updates.

Defensive priority

High / urgent. CISA has listed this CVE in the Known Exploited Vulnerabilities catalog and provided a remediation due date of 2022-05-03 in the supplied record. Any remaining exposure should be prioritized immediately.

Recommended defensive actions

  • Inventory all applications, services, and appliances that use Apache Shiro.
  • Determine whether any deployed Shiro instances are affected and still reachable in production.
  • Apply vendor-recommended updates or mitigations as directed by the product maintainer.
  • Prioritize internet-facing, externally reachable, and business-critical systems first.
  • Verify remediation by rescanning, checking software versions, and confirming the vulnerable component is no longer present.
  • Review logs and endpoint telemetry for signs of suspicious activity on exposed systems.
  • Document any exceptions and track them to closure with compensating controls.

Evidence notes

The supplied CISA KEV record identifies vendorProject 'Apache', product 'Shiro', vulnerabilityName 'Apache Shiro Code Execution Vulnerability', dateAdded '2021-11-03', dueDate '2022-05-03', and requiredAction 'Apply updates per vendor instructions.' The corpus also provides CVE and NVD reference links, but no CVSS score, vendor advisory URL, affected version list, or exploit details. Dates in this debrief are taken only from the supplied CVE/KEV metadata.

Sources and references

Verified primary and authoritative sources

  • CVE-2016-4437 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2016-4437

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2016-4437 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2016-4437

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.