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Fencer Vulns
medium 5.3

CVE-2024-38520 json

SoftEther VPN with L2TP - 2.75x Amplification

published 2024-06-26 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-37389

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

SoftEtherVPN is a an open-source cross-platform multi-protocol VPN Program. When SoftEtherVPN is deployed with L2TP enabled on a device, it introduces the possibility of the host being used for amplification/reflection traffic generation because it will respond to every packet with two response packets that are larger than the request packet size. These sorts of techniques are used by external actors who generate spoofed source IPs to target a destination on the internet. This vulnerability has been patched in version 5.02.5185.

Patch / fix

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.51% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected products

  • SoftEtherVPN SoftEtherVPN
  • softether vpn

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.