CVE-2026-3502
TrueConf Client downloads application update code and applies it without performing verification.
High
Known exploited
- Severity
- 7.8 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 5.85%
- Chance of exploitation in the next 30 days. Higher than 93.17% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Apr 2, 2026
- Weakness
- CWE-494 Download of Code Without Integrity Check
- Fix
- None yet
- No fixed version published
Exploited in the wild. TrueConf Client Download of Code Without Integrity Check Vulnerability (TrueConf Client). 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. Due for U.S. federal agencies by Apr 16, 2026.
Description
TrueConf Client downloads application update code and applies it without performing verification. 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.
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 7.8
CVSS:3.1/AV:A/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:L
- Attack vector
- Adjacent
- Attack complexity
- Low
- Privileges required
- High
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
Weakness
CWE-494: Download of Code Without Integrity Check
The product downloads source code or an executable from a remote location and executes the code without sufficiently verifying the origin and integrity of the code.
How to prevent it
- Implementation: Perform proper forward and reverse DNS lookups to detect DNS spoofing.
- Architecture and Design, Operation: Encrypt the code with a reliable encryption scheme before transmitting. This will only be a partial solution, since it will not detect DNS spoofing and it will not prevent your code from being modified on the hosting site.
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482]. Speficially, it may be helpful to use tools or frameworks to perform integrity checking on the transmitted code. When providing the code that is to be downloaded, such as for automatic updates of the software, then use cryptographic signatures for the code and modify the download clients to verify the signatures. Ensure that the implementation does not contain CWE-295, CWE-320, CWE-347, and related weaknesses. Use code signing technologies such as Authenticode. See references [REF-454] [REF-455] [REF-456].
- Architecture and Design, Operation: Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
- Architecture and Design, Operation: Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software. OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
References
Advisories
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-pq7j-f95f-qfcv Claude Code: Plugin Hash Pin Bypass Allows Bypass of Hash Pinning | High | Same weakness, CWE-494 |
| GHSA-662p-52hx-cmh2 Nginx UI: Self-upgrade runs an unsigned binary verified only by a same-origin digest → RCE via a compromised mirror or MITM | High | Same weakness, CWE-494 |
| GHSA-x9r9-c232-4q39 Hugging Face Transformers downloads custom generation code before trust consent | High | Same weakness, CWE-494 |
| GHSA-5wp5-5229-5g6q NLTK: Missing Post-Download Integrity Verification Allows Malicious Package Injection | Medium | Same weakness, CWE-494 |
| GHSA-w466-c33r-3gjp pnpm: Project env lockfile can short-circuit package-manager resolution and execute lockfile-selected pnpm bytes | High | Same weakness, CWE-494 |
| GHSA-gj8w-mvpf-x27x pnpm: Repository-controlled configDependencies can select a pacquet native install engine | High | Same weakness, CWE-494 |
| CVE-2025-15556 Notepad++ < 8.8.9 WinGUp Updater Lacks Update Integrity Verification | High Known exploited | Same weakness, CWE-494 |
| GHSA-7vhp-vf5g-r2fw pnpm Has Lockfile Integrity Bypass that Allows Remote Dynamic Dependencies | High | Same weakness, CWE-494 |
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