What is CVE-2026-3502?
Zero-day vulnerability in TrueConf Windows client (versions prior to 8.5.3.884) where the application downloads and applies update code without performing integrity or authenticity verification (CWE-494). Exploited in Operation TrueChaos by a Chinese-nexus threat actor targeting Southeast Asian government entities. The attacker compromised an on-premises TrueConf server and replaced the legitimate client update package with a trojanized Inno Setup installer that deployed a multi-stage attack chain including DLL side-loading via poweriso.exe, UAC bypass via iscsicpl.exe, and Havoc C2 implant communicating to Alibaba and Tencent Cloud infrastructure. TrueConf serves approximately 100,000 organizations globally across government, military, critical infrastructure, banking, and enterprise sectors. CISA added this CVE to the KEV catalog on April 2, 2026 with a federal remediation deadline of April 16, 2026. Patched in TrueConf Windows client version 8.5.3.
The record classifies CVE-2026-3502 under weakness class CWE-494. Its CVSS v3 base vector states that the flaw is reachable from an adjacent network, needs high-privilege credentials, needs a user to take an action first, and has high impact on confidentiality, integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 189 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.8 — HIGH
CVSS:3.1/AV:A/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L - EPSS (FIRST)
- 1.4% probability of exploitation in the next 30 days, higher than 81.0% of all scored CVEs
- CISA KEV
- Listed since 2026-04-02, federal remediation deadline 2026-04-16
- Threadlinqs priority
- 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- Published
- 2026-03-30, last modified 2026-04-03
Is CVE-2026-3502 being exploited?
CISA added CVE-2026-3502 to the Known Exploited Vulnerabilities catalog on 2026-04-02, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-04-16 under BOD 22-01. It currently carries a trending score of 40 in the Threadlinqs vulnerability feed.
Affected products and versions
- Trueconf: Trueconf
How to fix CVE-2026-3502
The record marks a vendor fix as available for CVE-2026-3502. Patch reference: https://trueconf.com/blog/update/trueconf-8-5. Vendor advisory: https://trueconf.com/blog/update/trueconf-8-5. Because CVE-2026-3502 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-04-16. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-3502
2 tracked threats in the Threadlinqs corpus reference CVE-2026-3502, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Seeded from threat-derived and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.