CVE-2017-9791 — Apache Struts 1 Improper Input Validation 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.

• Documented mitigation — struts.apache.org (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: Aug 10, 2022 — passed 1527 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 Struts, Maven Org.apache.struts:struts2-struts1-plugin).
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 matching the vulnerability class (input validation), 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-20 · Improper Input Validation

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 98.91%

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 Feb 10, 2022 (KEV listing): exploitation may have started earlier.

Timeline

What happened to this CVE, newest first.

• 2026
• Affected products added · maven/org.apache.struts:struts2-struts1-plugin
  Oct 13, 2026 · GitHub Security Advisories
• Fix documented
  Oct 13, 2026 · NIST National Vulnerability Database
• Affected products added · apache/struts
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · Published → Analyzed
  Oct 13, 2026 · NIST National Vulnerability Database
• Record published
  Oct 13, 2026
• Affected products added · apache software foundation/apache struts
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• 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
• 2022
• Added to CISA KEV catalog
  Feb 9, 2022 · CISA
• 2017
• CVE published
  Jul 10, 2017 · apache

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

14 on the record

• struts.apache.org/docs/s2-048.html
  x_refsource_CONFIRM, Mitigation, Vendor Advisory, CVE Program (cve.org) e CISA ADP
• www.oracle.com/technetwork/security-advisory/alert-cve-2017-9805-3889403.html
  x_refsource_CONFIRM, Patch, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• www.cisa.gov/known-exploited-vulnerabilities-catalog
  US Government Resource, NIST National Vulnerability Database
• github.com/advisories/GHSA-29rm-6752-gvwv
  GitHub Security Advisories
• www.exploit-db.com/exploits/44643/
  exploit, x_refsource_EXPLOIT-DB, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• github.com/apache/struts/commit/ffe0e20edd9d5386f4410fddd970286a69373243
  GitHub Security Advisories
• www.exploit-db.com/exploits/44643
  GitHub Security Advisories
• security.netapp.com/advisory/ntap-20180706-0002/
  x_refsource_CONFIRM, Third Party Advisory, CVE Program (cve.org) e CISA ADP
• www.securitytracker.com/id/1038838
  vdb-entry, x_refsource_SECTRACK, Broken Link, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• www.securityfocus.com/bid/99484
  vdb-entry, x_refsource_BID, Broken Link, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• security.netapp.com/advisory/ntap-20180706-0002
  GitHub Security Advisories
• www.exploit-db.com/exploits/42324/
  exploit, x_refsource_EXPLOIT-DB, Third Party Advisory, VDB Entry, CVE Program (cve.org) e CISA ADP
• www.exploit-db.com/exploits/42324
  GitHub Security Advisories
• nvd.nist.gov/vuln/detail/CVE-2017-9791
  GitHub Security Advisories

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-104714 Apache Struts: Shared message formatter exposes date and time values across concurrent requests 10d
• Critical CVE-2026-104711 Apache Struts: OGNL injection in the legacy RESTful action mapper 10d
• High CVE-2026-104712 Apache Struts: Disproportionate response size when rendering BigDecimal request parameters 10d
• Medium CVE-2026-104713 Apache Struts: Unbounded request body read in the REST plugin 10d
• Medium CVE-2026-73632 Exposure of data element to wrong session vulnerability in the JSON plugin of Apache… Aug 15, 2026
• High CVE-2026-73634 Uncontrolled Resource Consumption in Apache Software Foundation Struts Aug 15, 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-2017-9791 is "Apache Struts 1 Improper Input Validation Vulnerability", rated Critical. It affects Struts (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 98.91% 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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