Exploited CVEs / RARLAB / CVE-2023-38831

CVE-2023-38831

RARLAB WinRAR Code Execution Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2023-09-14 (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

HighCISA KEVRansomware

7.8

CVSS base

98%

EPSS exploit probability

High

Severity

2023-08-24

Added to KEV

2023-09-14 (past due)

CISA due date

Actively exploited RARLAB WinRAR vulnerability, High severity, CVSS 7.8. Added to the CISA KEV catalog 2023-08-24.

Senserva AI read on CVE-2023-38831 CISA required action Official fix for CVE-2023-38831 Admin questions

Senserva AI Opinion for CVE-2023-38831

WinRAR users triggered this one by viewing what looked like a benign file inside a ZIP archive, and with a 98% EPSS score and confirmed ransomware use it became a phishing staple within weeks. WinRAR has no centralized update mechanism, so patched versions must be pushed manually, and unmanaged installs stay vulnerable indefinitely. It is rated High Severity (CVSS 7.8) and was added to the KEV list in August 2023.

Do this: Inventory WinRAR installs across the fleet, upgrade or remove them, and block archive attachments from untrusted senders where possible.

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

Senserva AI Opinion and rich prompt for CVE-2023-38831

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

I run IT security. Facts for CVE-2023-38831, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2023-38831.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2023-38831: RARLAB WinRAR Code Execution Vulnerability
- Affected: RARLAB WinRAR
- Severity: High, CVSS 7.8; EPSS 30-day exploitation probability 98%
- Added to CISA KEV: 2023-08-24; federal remediation due 2023-09-14
- Ransomware-linked: YES
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
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 immediately

Exploited in the wild and used in ransomware campaigns.

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

Do this now: Move this ahead of everything else in the queue, then verify the fix actually landed on every exposed device.

Updated August 14, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2023-38831

Published: 2023-08-24
Last revised: 2023-08-24
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

2023-08-24 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 7.8; EPSS first scored at 97.8%
2026-07-24 EPSS 97.8% to 97.8%

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: 2023-09-14 (past due).

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Official fix for CVE-2023-38831

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

CISA KEV entry

Common questions about CVE-2023-38831

Is CVE-2023-38831 actively exploited?

Yes. CVE-2023-38831 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2023-08-24, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 98%. CISA also reports it is known to be used in ransomware campaigns.

What is the CISA deadline and required action for CVE-2023-38831?

CISA set the federal (BOD 22-01) remediation due date at 2023-09-14, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

What fixes CVE-2023-38831?

Check the vendor's security advisory for the patched WinRAR 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-2023-38831?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2023-38831'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 twice a day (5 AM and 3 PM US Central).

Scope and sources

More exploited RARLAB CVEs: CVE-2025-6218 CVE-2025-8088 CVE-2022-30333 CVE-2018-20250
All RARLAB exploited CVEs on one page: RARLAB 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.