CVE-2021-33879
Tencent GameLoop before 4.1.21.90 downloaded updates over an insecure HTTP connection. A...
Tencent GameLoop before 4.1.21.90 downloaded updates over an insecure HTTP connection. A malicious attacker in an MITM position could spoof the contents of an XML document describing an update package, replacing a download URL with one pointing to an arbitrary Windows executable. Because the only integrity check would be a comparison of the downloaded file's MD5 checksum to the one contained within the XML document, the downloaded executable would then be executed on the victim's machine.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
Tencent GameLoop before 4.1.21.90 downloaded updates over an insecure HTTP connection. A malicious attacker in an MITM position could spoof the contents of an XML document describing an update package, replacing a download URL with one pointing to an arbitrary Windows executable. Because the only integrity check would be a comparison of the downloaded file's MD5 checksum to the one contained within the XML document, the downloaded executable would then be executed on the victim's machine.
- Record
CVE-2021-33879- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 6.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-494
- Updated
- 2026-11-02
CVE List No score
Tencent GameLoop before 4.1.21.90 downloaded updates over an insecure HTTP connection. A malicious attacker in an MITM position could spoof the contents of an XML document describing an update package, replacing a download URL with one pointing to an arbitrary Windows executable. Because the only integrity check would be a comparison of the downloaded file's MD5 checksum to the one contained within the XML document, the downloaded executable would then be executed on the victim's machine.
- Record
CVE-2021-33879- Updated
- 2026-11-02
EUVDEUVD-2021-20553 No score
Tencent GameLoop before 4.1.21.90 downloaded updates over an insecure HTTP connection. A malicious attacker in an MITM position could spoof the contents of an XML document describing an update package, replacing a download URL with one pointing to an arbitrary Windows executable. Because the only integrity check would be a comparison of the downloaded file's MD5 checksum to the one contained within the XML document, the downloaded executable would then be executed on the victim's machine.
- Record
EUVD-2021-20553- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p52r-cj24-79f7 No score
Tencent GameLoop before 4.1.21.90 downloaded updates over an insecure HTTP connection. A...
Tencent GameLoop before 4.1.21.90 downloaded updates over an insecure HTTP connection. A malicious attacker in an MITM position could spoof the contents of an XML document describing an update package, replacing a download URL with one pointing to an arbitrary Windows executable. Because the only integrity check would be a comparison of the downloaded file's MD5 checksum to the one contained within the XML document, the downloaded executable would then be executed on the victim's machine.
- Record
GHSA-p52r-cj24-79f7- Weakness
- CWE-494
- Updated
- 2026-11-02
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | mmiszczyk/cve-2021-33879 | 2021-06-06 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-33879 is a high vulnerability (CVSS 8.1) in Tencent Gameloop, published June 6, 2021. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.20%, the 68th percentile. No source names a fixed version.