CVE-2026-3502
CVE-2026-3502 is a security flaw in TrueConf Client. Attackers can run their own code on TrueConf Client. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 2 Apr 2026.[1]
TrueConf Client is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. TrueConf has published a fix or advice.
Description
CISA calls it a download of code without integrity check in TrueConf Client. In its words: “TrueConf Client contains a download of code without integrity check vulnerability. An attacker who is able to influence the update delivery path can substitute a tampered update payload. If the payload is executed or installed by the updater, this may result in arbitrary code execution in the context of the updating process or user.”[1]
The underlying weakness is CWE-494, in MITRE’s list of common software weaknesses.[2]
It scores 7.8 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by the organisation that published the CVE using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; TrueConf’s advisory has them[3]. CISA names the product as TrueConf Client.
Most families won’t have TrueConf Client; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 2 Apr 2026, 3 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 16 Apr 2026 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 6%. That’s in the top 7% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
CISA doesn’t say who was attacked, or how.
Fix
TrueConf has published a fix or advice.[3] CISA’s required action: “Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.”[1]
- Check whether you use it.TrueConf Client is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 16 Apr 2026 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 7.8.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at 6%.[4] |
See also
Other TrueConf flaws
- CVE-2026-72530, TrueConf Server: code injection ·
- CVE-2026-72529, TrueConf Server: missing authentication for critical function ·
Similar flaws
- CVE-2025-15556, Notepad++: download of code without integrity check ·
- CVE-2022-40799, D-Link DNR-322L: download of code without integrity check ·
- CVE-2021-44168, Fortinet FortiOS: arbitrary file download ·
Every TrueConf flaw on CISA’s list · Everything added in April 2026
References
- ^ Cybersecurity and Infrastructure Security Agency. “TrueConf Client Download of Code Without Integrity Check Vulnerability”. Known Exploited Vulnerabilities Catalog, added 2 Apr 2026.
- ^ National Institute of Standards and Technology. “CVE-2026-3502 Detail”. National Vulnerability Database, published 30 Mar 2026.
- ^ TrueConf. Advisories and fixes: trueconf.com, trueconf.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.058, percentile 93.2, 31 Oct 2026.
- CVE Program. “CVE-2026-3502”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.