CVE-2023-38831 — Rarlab Winrar
CISA KEVRansomwareAs of 2025-10-31, CVE-2023-38831 is a HIGH-severity vulnerability in Rarlab Winrar, CVSS v3.1 7.8, EPSS 93.8% (99.8th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-08-24), with a US federal remediation deadline of 2023-09-14, and CISA links it to known ransomware campaigns. Threadlinqs Intelligence links 3 tracked threat campaigns to CVE-2023-38831, most recently “Russia (GRU Unit 26165 / APT28) Runs Multi-Vector Surveillance, Intimidation, Sabotage and Cyber Espionage Campaign Against Europe's Ukraine Defence Supply Chain”.
Last updated: 2025-10-31
What is CVE-2023-38831?
RARLAB WinRAR before 6.23 allows attackers to execute arbitrary code when a user attempts to view a benign file within a ZIP archive. The issue occurs because a ZIP archive may include a benign file (such as an ordinary .JPG file) and also a folder that has the same name as the benign file, and the contents of the folder (which may include executable content) are processed during an attempt to access only the benign file. This was exploited in the wild in April through October 2023.
The record classifies CVE-2023-38831 under weakness classes CWE-345, CWE-351. Its CVSS v3 base vector states that the flaw requires local access to the host, needs no prior authentication, needs a user to take an action first, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 1117 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 93.8% probability of exploitation in the next 30 days, higher than 99.8% of all scored CVEs
- CISA KEV
- Listed since 2023-08-24, federal remediation deadline 2023-09-14 — used in known ransomware campaigns
- Threadlinqs priority
- 10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
- Published
- 2023-08-23, last modified 2025-10-31
Is CVE-2023-38831 being exploited?
CISA added CVE-2023-38831 to the Known Exploited Vulnerabilities catalog on 2023-08-24, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2023-09-14 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. It currently carries a trending score of 40 in the Threadlinqs vulnerability feed.
Affected products and versions
- Rarlab: Winrar
How to fix CVE-2023-38831
Because CVE-2023-38831 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2023-09-14. No vendor patch reference has been recorded for CVE-2023-38831 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2023-38831
3 tracked threats in the Threadlinqs corpus reference CVE-2023-38831, either in the campaign’s CVE list or as an indicator on the campaign record.
- Russia (GRU Unit 26165 / APT28) Runs Multi-Vector Surveillance, Intimidation, Sabotage and Cyber Espionage Campaign Against Europe's Ukraine Defence Supply Chain — HIGH · 2026-08-16
- Cyble H1 2026 Threat Actor Landscape: 261 Tracked Groups, Five Most Active Actors Profiled — HIGH · 2026-07-27
- APT28/UAC-0001 Sustained Cyber Espionage Against Ukraine & EU (2024-2026 New TTPs) — HIGH · 2026-02-12
Sources
Seeded from nvd and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.
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