Exploited CVEs / Apache / CVE-2017-9791

CVE-2017-9791

Apache Struts 1 Improper Input Validation Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2022-08-10 (that deadline has passed); treat that date as the outer bound for your own environment. Check the vendor security advisory for the fix.

Risk summary

CriticalCISA KEV

9.8

CVSS v3 base

99%

EPSS exploit probability

Critical

Severity

2022-02-10

Added to KEV

2022-08-10 (past due)

CISA due date

Actively exploited Apache Struts 1 vulnerability, Critical severity, CVSS v3 9.8. Added to the CISA KEV catalog 2022-02-10.

Senserva AI read on CVE-2017-9791 CISA required action Official fix for CVE-2017-9791 Admin questions

Senserva AI Opinion for CVE-2017-9791

Apache Struts 1 reached end of life long before this flaw was disclosed, so applications still running the Struts 1 plugin have no supported upgrade path away from this Critical (CVSS 9.8) remote code execution bug. Its 99% EPSS score and 2022-02-10 KEV confirmation show attackers still find live targets. A malicious field value passed to ActionMessage is enough to run code.

Do this: Identify applications still built on Struts 1 and prioritize migrating or isolating them, since no patched Struts 1 exists.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2017-9791

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2017-9791, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2017-9791.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed once a day (early morning US Central)):
- CVE-2017-9791: Apache Struts 1 Improper Input Validation Vulnerability
- Affected: Apache Struts 1
- Severity: Critical, CVSS v3 9.8; EPSS 30-day exploitation probability 99%
- Added to CISA KEV: 2022-02-10; federal remediation due 2022-08-10
- Ransomware-linked: no
- CISA required action: Apply updates per vendor instructions.
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch now

Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.

No vendor fix is mapped yet. This page refreshes daily and will name the patch the day one is published.

Do this now: Federal remediation deadline 2022-08-10; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated September 3, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2017-9791

Published: 2022-02-10
Last revised: 2022-02-10
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

Drawn by Senserva Vivid from the Senserva change record. Hover any point for its date and value.

2022-02-10 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 9.8; EPSS first scored at 98.9%
2026-07-24 EPSS 98.9% to 98.8%
2026-08-07 EPSS 98.8% to 98.9%
2026-08-11 CVSS 9.8 to 0.0
2026-08-12 CVSS 0.0 to 9.8

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2022-08-10 (past due).

Apply updates per vendor instructions.

Official fix for CVE-2017-9791

Check the vendor's security advisory channel for the patched Struts 1 versions and workarounds.

CISA KEV entry

Common questions about CVE-2017-9791

Is CVE-2017-9791 actively exploited?

Yes. CVE-2017-9791 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2022-02-10, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 99%.

What is the CISA deadline and required action for CVE-2017-9791?

CISA set the federal (BOD 22-01) remediation due date at 2022-08-10, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.

What fixes CVE-2017-9791?

Check the vendor's security advisory for the patched Struts 1 versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2017-9791?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2017-9791's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed once a day (early morning US Central).

Scope and sources

More exploited Apache CVEs: CVE-2026-34486 CVE-2026-34197 CVE-2024-38475 CVE-2025-24813 CVE-2024-45195 CVE-2024-27348 CVE-2024-38856 CVE-2024-32113
All Apache exploited CVEs on one page: Apache vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.