CVE-2023-4194: A flaw was found in the Linux kernel's TUN/TAP functionality

Q: How do I fix CVE-2023-4194?

linux kernel: upgrade to newer than 6.4; enterprise linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2023-4194 being exploited?

CVE-2023-4194 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-4194 affect?

CVE-2023-4194 affects linux kernel, enterprise linux, fedora. Severity is medium (CVSS 5.5). A flaw was found in the Linux kernel's TUN/TAP functionality. This issue could allow a local user to bypass network filters and gain unauthorized access to some resources. The original patches fixing CVE-2023-1076 are incorrect or incomplet

Q: How urgent is CVE-2023-4194?

Priority 29/100. On your watchlist

Routine

MEDIUM 5.5WATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2023-4194 is a medium-severity flaw (CVSS 5.5) affecting linux kernel, enterprise linux, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in the Linux kernel's TUN/TAP functionality. This issue could allow a local user to bypass network filters and gain unauthorized access to some resources. The original patches fixing CVE-2023-1076 are incorrect or incomplete. The problem is that the following upstream commits - a096ccca6e50 ("tun: tun_chr_open(): correctly initialize socket uid"), - 66b2c338adce ("tap: tap_open(): correctly initialize socket uid"), pass "inode->i

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-843, CWE-863
Published	2023-08-07
Last modified	2026-11-03

Publisher (CNA): Red Hat, Inc. · Vendor: debian · fedoraproject · linux · redhat

Last updated 2026-11-03 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-08-07 14:15 UTCPublished CVE record published
2026-11-03 05:18 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: <= 6.4 · 6.5 rc1 · 6.5 rc2 · 6.5 rc3 · 6.5 rc4

Fixed in: newer than 6.4

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

redhat enterprise linux MITIGATE

Affected: 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 8.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

fedoraproject fedora MITIGATE

Affected: 37 · 38

Fixed in: no fixed release known

Safe to downgrade to: a release before 37

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

debian debian linux MITIGATE

Affected: 10.0 · 11.0 · 12.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-4194?

linux kernel: upgrade to newer than 6.4; enterprise linux: mitigate or apply the listed mitigation; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-4194 being exploited?

CVE-2023-4194 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-4194 affect?

CVE-2023-4194 affects linux kernel, enterprise linux, fedora. Severity is medium (CVSS 5.5). A flaw was found in the Linux kernel's TUN/TAP functionality. This issue could allow a local user to bypass network filters and gain unauthorized access to some resources. The original patches fixing CVE-2023-1076 are incorrect or incomplet

How urgent is CVE-2023-4194?

Priority 29/100. On your watchlist

Software pages

Linux kernel vulnerabilities · Debian vulnerabilities

Related CVEs

CVE-2023-5197 HIGH 7.8 MITIGATE UPGRADE A use-after-free vulnerability in the Linux kernel's netfilter: nf_tables component can be exploited to achiev
CVE-2023-45862 MEDIUM 5.5 UPGRADE MITIGATE An issue was discovered in drivers/usb/storage/ene_ub6250.c for the ENE UB6250 reader driver in the Linux kern
CVE-2023-1077 HIGH 7.0 UPGRADE MITIGATE In the Linux kernel, pick_next_rt_entity() may return a type confused entry, not detected by the BUG_ON condit
CVE-2022-36280 MEDIUM 6.3 UPGRADE MITIGATE An out-of-bounds(OOB) memory access vulnerability was found in vmwgfx driver in drivers/gpu/vmxgfx/vmxgfx_kms.
CVE-2022-2905 MEDIUM 5.5 UPGRADE MITIGATE An out-of-bounds memory read flaw was found in the Linux kernel's BPF subsystem in how a user calls the bpf_ta

References

← Back to latest CVEs