CVE-2023-1523: Using the TIOCLINUX ioctl request, a malicious snap could inject contents into the input of the controlling te

Q: How do I fix CVE-2023-1523?

snapd: upgrade to 2.59.5; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2023-1523 being exploited?

CVE-2023-1523 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-2023-1523 affect?

CVE-2023-1523 affects snapd, ubuntu linux. Severity is critical (CVSS 10.0). Using the TIOCLINUX ioctl request, a malicious snap could inject contents into the input of the controlling terminal which could allow it to cause arbitrary commands to be executed outside of the snap sandbox after the snap exits. Graphical

Q: How urgent is CVE-2023-1523?

Priority 71/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 10.0REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2023-1523 is a critical-severity flaw (CVSS 10.0) affecting snapd, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Using the TIOCLINUX ioctl request, a malicious snap could inject contents into the input of the controlling terminal which could allow it to cause arbitrary commands to be executed outside of the snap sandbox after the snap exits. Graphical terminal emulators like xterm, gnome-terminal and others are not affected - this can only be exploited when snaps are run on a virtual console.

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	10.0 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.4% (top 27%)
CISA exploited list	No
Weakness	CWE-74
Published	2023-09-01
Last modified	2026-06-17

Publisher (CNA): Canonical Ltd. · Vendor: canonical

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-09-01 19:15 UTCPublished CVE record published
2026-06-17 05:28 UTCUpdated Record last modified

canonical snapd UPGRADE

Affected: < 2.59.5

Fixed in: 2.59.5

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy snapd || rpm -q snapd || snapd --version

2. UPGRADE to 2.59.5 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade snapd

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade snapd

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

canonical ubuntu linux MITIGATE

Affected: 16.04 · 18.04 · 20.04 · 22.04 · 22.10 · 23.04

Fixed in: no fixed release known

Safe to downgrade to: a release before 16.04

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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · root · FIXED · 6.40.04-7.fc46 · FEDORA-2026-7329868400 · source

sudo dnf upgrade --advisory=FEDORA-2026-7329868400

Ubuntu 20.04 · snapd · FIXED · 2.58+20.04.1

sudo apt update && sudo apt install --only-upgrade snapd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' snapd)" ge "2.58+20.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · snapd · FIXED · 2.58+22.04.1

sudo apt update && sudo apt install --only-upgrade snapd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' snapd)" ge "2.58+22.04.1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · snapd · NO FIX YET

Debian 13 · snapd · FIXED · 2.59.5-1

sudo apt update && sudo apt install --only-upgrade snapd dpkg --compare-versions "$(dpkg-query -W -f='${Version}' snapd)" ge "2.59.5-1" && echo PATCHED || echo STILL-VULNERABLE

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: marc.info/?l=oss-security&m=167879021709955&w=2

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-2023-1523?

snapd: upgrade to 2.59.5; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-1523 being exploited?

CVE-2023-1523 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-2023-1523 affect?

CVE-2023-1523 affects snapd, ubuntu linux. Severity is critical (CVSS 10.0). Using the TIOCLINUX ioctl request, a malicious snap could inject contents into the input of the controlling terminal which could allow it to cause arbitrary commands to be executed outside of the snap sandbox after the snap exits. Graphical

How urgent is CVE-2023-1523?

Priority 71/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Ubuntu vulnerabilities

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References

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