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Vulnerability record · CVE-2020-1749 · published 9 September 2020

CVE-2020-1749: Linux kernel cleartext transmission vulnerability

Linux · Linux Kernel

A flaw was found in the Linux kernel's implementation of some networking protocols in IPsec, such as VXLAN and GENEVE tunnels over IPv6. When an encrypted tunnel is created between two hosts, the kernel isn't correctly routing tunneled data over the encrypted link; rather sending the data unencrypted. This would allow anyone in between the two endpoints to read the traffic unencrypted. The main threat from this vulnerability is to data confidentiality.

7.5 CVSS 3.1 High EPSS 1.2% · top 32.1% CWE-319 · Cleartext transmission
7.5CVSS 3.1 base score, v2 5.0
1.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

A flaw was found in the Linux kernel's implementation of some networking protocols in IPsec, such as VXLAN and GENEVE tunnels over IPv6. When an encrypted tunnel is created between two hosts, the kernel isn't correctly routing tunneled data over the encrypted link; rather sending the data unencrypted. This would allow anyone in between the two endpoints to read the traffic unencrypted. The main threat from this vulnerability is to data confidentiality.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-1749 Issue TrackingPatchThird Party Advisory
https://security.netapp.com/advisory/ntap-20201222-0001/
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-1749 Issue TrackingPatchThird Party Advisory
https://security.netapp.com/advisory/ntap-20201222-0001/

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Source: NIST National Vulnerability Database (record CVE-2020-1749), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.