01 Record

CVE-2021-3773

A flaw in netfilter could allow a network-connected attacker to infer openvpn connection endpoint information for further use in traditional network attacks.

UnratedPUBLISHEDCNA: redhat

CNA base scoreUnratedNo CNA CVSS vector

View raw JSON

02 Description

A flaw in netfilter could allow a network-connected attacker to infer openvpn connection endpoint information for further use in traditional network attacks.

03 Exploitation and scoring

Exploitation

Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.

SSVC decision

ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

5.27% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 92.3% of scored records. A rank, not a probability.

NVD base score

9.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2022-02-16 18:35Z4 YR AGO

Last updated

2025-03-28 15:02Z1 YR AGO

Reserved

2021-09-06

Assigning CNA

redhat

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

CWE-200Exposure of Sensitive Information to an Unauthorized ActorClass

Data version

5.1

Document digest

acaf6dd33e574d64d7563150e677edea554a71e0632a1b87795a494e65bbb5cb

05 Affected products

VendorProductVersionsPlatforms

n/akernelkernel 5.14.0-49.el9, kernel 5.15.15-100.fc34, kernel 5.15.15-200.fc35—

06 References

bugzilla.redhat.comhttps://bugzilla.redhat.com/show_bug.cgi?id=2004949
www.oracle.comhttps://www.oracle.com/security-alerts/cpujul2022.html
citizenlab.cahttps://citizenlab.ca/2024/07/vulnerabilities-in-vpns-paper-presented-at-the-privacy-enhancing-technologies-symposium-2024/
security.netapp.comhttps://security.netapp.com/advisory/ntap-20250328-0004/

07 Fixed in

AlmaLinux 8

bpftool
Fixed in 4.18.0-372.9.1.el8
kernel
Fixed in 4.18.0-372.9.1.el8
kernel-abi-stablelists
Fixed in 4.18.0-372.9.1.el8
kernel-core
Fixed in 4.18.0-372.9.1.el8
kernel-cross-headers
Fixed in 4.18.0-372.9.1.el8
kernel-debug
Fixed in 4.18.0-372.9.1.el8
kernel-debug-core
Fixed in 4.18.0-372.9.1.el8
kernel-debug-devel
Fixed in 4.18.0-372.9.1.el8
kernel-debug-modules
Fixed in 4.18.0-372.9.1.el8
kernel-debug-modules-extra
Fixed in 4.18.0-372.9.1.el8
kernel-devel
Fixed in 4.18.0-372.9.1.el8
kernel-doc
Fixed in 4.18.0-372.9.1.el8
kernel-headers
Fixed in 4.18.0-372.9.1.el8
kernel-modules
Fixed in 4.18.0-372.9.1.el8
kernel-modules-extra
Fixed in 4.18.0-372.9.1.el8
kernel-tools
Fixed in 4.18.0-372.9.1.el8
kernel-tools-libs
Fixed in 4.18.0-372.9.1.el8
kernel-tools-libs-devel
Fixed in 4.18.0-372.9.1.el8
perf
Fixed in 4.18.0-372.9.1.el8
python3-perf
Fixed in 4.18.0-372.9.1.el8

Arch Linux

openvpn
No fix yet

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

CloudLinux 8

bpftool
Fixed in 4.18.0-372.9.1.el8
kernel
Fixed in 4.18.0-372.9.1.el8
kernel-abi-stablelists
Fixed in 4.18.0-372.9.1.el8
kernel-core
Fixed in 4.18.0-372.9.1.el8
kernel-cross-headers
Fixed in 4.18.0-372.9.1.el8
kernel-debug
Fixed in 4.18.0-372.9.1.el8
kernel-debug-core
Fixed in 4.18.0-372.9.1.el8
kernel-debug-devel
Fixed in 4.18.0-372.9.1.el8
kernel-debug-modules
Fixed in 4.18.0-372.9.1.el8
kernel-debug-modules-extra
Fixed in 4.18.0-372.9.1.el8
kernel-devel
Fixed in 4.18.0-372.9.1.el8
kernel-doc
Fixed in 4.18.0-372.9.1.el8
kernel-headers
Fixed in 4.18.0-372.9.1.el8
kernel-modules
Fixed in 4.18.0-372.9.1.el8
kernel-modules-extra
Fixed in 4.18.0-372.9.1.el8
kernel-tools
Fixed in 4.18.0-372.9.1.el8
kernel-tools-libs
Fixed in 4.18.0-372.9.1.el8
kernel-tools-libs-devel
Fixed in 4.18.0-372.9.1.el8
perf
Fixed in 4.18.0-372.9.1.el8
python3-perf
Fixed in 4.18.0-372.9.1.el8

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.