CVE-2016-4437 — Apache Shiro Code Execution Vulnerability

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Maven Org.apache.shiro:shiro-core: fixed in version 1.2.5 — github.com (GitHub Security Advisories)

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: May 3, 2022 — passed 1626 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Aurora, Apache Software Foundation Shiro, Red Hat Fuse…).
2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
4. Apply the fixed version or the patch documented under Remediation.
5. EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
6. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-321

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 93.04%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Hunt retroactively in logs from before Nov 3, 2021 (KEV listing): exploitation may have started earlier.

Timeline

What happened to this CVE, newest first.

• 2026
• Fix documented
  Oct 13, 2026 · GitHub Security Advisories
• Affected products added · maven/org.apache.shiro:shiro-core
  Oct 13, 2026 · GitHub Security Advisories
• Affected products added · apache/aurora, apache/shiro, redhat/fuse, redhat/jboss middleware text-only advisories
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · Published → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Record published
  Oct 13, 2026
• CVSS changed · 9.8
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Source status changed · → Published
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Added to CISA KEV (detected)
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• Record created in this database
  Oct 13, 2026 · CISA Known Exploited Vulnerabilities
• 2021
• Added to CISA KEV catalog
  Nov 2, 2021 · CISA
• 2016
• CVE published
  Jun 7, 2016 · redhat

Source activity

Repeated readings are counted rather than listed.

• 3× References added · Oct 13, 2026 – Oct 13, 2026
• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

11 on the record

• www.cisa.gov/known-exploited-vulnerabilities-catalog
  US Government Resource, NIST National Vulnerability Database
• lists.apache.org/thread.html/ef3a800c7d727a00e04b78e2f06c5cd8960f09ca28c9b69d94c3c4c4%
  mailing-list, x_refsource_MLIST, Mailing List, CVE Program (cve.org) e CISA ADP
• rhn.redhat.com/errata/RHSA-2016-2036.html
  vendor-advisory, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• github.com/advisories/GHSA-p836-389h-j692
  GitHub Security Advisories
• www.securityfocus.com/archive/1/538570/100/0/threaded
  mailing-list, x_refsource_BUGTRAQ, Broken Link, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• packetstormsecurity.com/files/137310/Apache-Shiro-1.2.4-Information-Disclosure.html
  x_refsource_MISC, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• lists.apache.org/thread.html/ef3a800c7d727a00e04b78e2f06c5cd8960f09ca28c9b69d94c3c4c4@
  GitHub Security Advisories
• www.securityfocus.com/bid/91024
  vdb-entry, x_refsource_BID, Broken Link, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• packetstormsecurity.com/files/157497/Apache-Shiro-1.2.4-Remote-Code-Execution.html
  x_refsource_MISC, Exploit, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• nvd.nist.gov/vuln/detail/CVE-2016-4437
  GitHub Security Advisories
• rhn.redhat.com/errata/RHSA-2016-2035.html
  vendor-advisory, x_refsource_REDHAT, Third Party Advisory, CVE Program (cve.org) e CISA ADP

Elsewhere on this site

Related CVEs (same products)

• Low CVE-2026-56130 Apache Shiro: Remember-me cookie isn't checked for expiry on the server Jun 25, 2026
• High CVE-2026-56091 Apache Shiro: Authentication bypass in Guice-Web integration Jun 25, 2026
• Critical CVE-2026-49268 Apache Shiro: LDAP DN Injection in DefaultLdapRealm Jun 17, 2026
• High CVE-2026-41731 In Spring for Apache Kafka, overly broad trusted-package matching in header mappers exposes JDK classes to deserialization Jun 9, 2026
• Medium CVE-2026-48589 Apache Shiro: Jakarta EE open redirect via untrusted Referer in post-login redirect flow May 25, 2026
• Medium CVE-2026-44598 Apache Shiro Jakarta EE module: Open redirect and SSRF (requires valid credentials) May 25, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2016-4437 is "Apache Shiro Code Execution Vulnerability", rated Critical. It affects Aurora (Apache Software Foundation); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.8 describes technical severity. EPSS 93.04% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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