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CVE-2026-4480: A flaw was found in the Samba printing subsystem

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This week
CRITICAL 9.0REMOTEWATCHLISTDOWNGRADEUPGRADEMITIGATE

CVE-2026-4480 is a critical-severity flaw (CVSS 9.0) affecting openshift container platform, samba, enterprise linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in the Samba printing subsystem. Samba passes the client-controlled job description string to the command configured with the "print command" setting via the "%J" substitution character without escaping shell meta characters. A remote attacker could exploit this vulnerability by sending a specially crafted print job description that contains unescaped shell characters. This could lead to remote code execution on the affected syst

Why this priority

  • Critical severity
  • EPSS top 3%: very likely to be exploited
  • Public exploit reference
  • Remotely exploitable, no login, no user action
  • On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score9.0 (Critical)
Attack vectorNetwork (remote)
Attack complexityHigh
Privileges neededNone
User interactionNone
EPSS exploit chance13.9% (top 3%)
CISA exploited listNo
WeaknessCWE-78
Published2026-05-26
Last modified2026-09-01
Publisher (CNA): Red Hat, Inc. · Vendor: redhat · samba

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Last updated 2026-09-01 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

redhat openshift container platform DOWNGRADE
Affected: 4.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 4.0
1. Check installed version
apt-cache policy openshift-container-platform || rpm -q openshift-container-platform || openshift-container-platform --version
2. No fixed release: DOWNGRADE to a release before 4.0 (Debian / Ubuntu)
apt-cache madison openshift-container-platform sudo apt install openshift-container-platform=<VERSION_BEFORE_4.0> sudo apt-mark hold openshift-container-platform
2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list openshift-container-platform sudo dnf downgrade openshift-container-platform-<VERSION_BEFORE_4.0> sudo dnf versionlock add openshift-container-platform
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
samba samba UPGRADE
Affected: >= 4.1.0 and < 4.2.1
Fixed in: 4.2.1
Safe to downgrade to: a release before 4.1.0
1. Check installed version
apt-cache policy samba || rpm -q samba || samba --version
2. UPGRADE to 4.2.1 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade samba
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade samba
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 4.1.0 (Debian / Ubuntu)
apt-cache madison samba sudo apt install samba=<VERSION_BEFORE_4.1.0> sudo apt-mark hold samba
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list samba sudo dnf downgrade samba-<VERSION_BEFORE_4.1.0> sudo dnf versionlock add samba
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
redhat enterprise linux MITIGATE
Affected: 7.0 · 8.0 · 9.0 · 10.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 7.0
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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.
Fedora ELN · clash-meta · FIXED · 1.19.33-1.eln159 · FEDORA-2026-7dfb64c5e1 · source
sudo dnf upgrade --advisory=FEDORA-2026-7dfb64c5e1
Fedora 46 · vulkan-utility-libraries · FIXED · 1.4.363.0-1.fc46 · FEDORA-2026-994176daf5 · source
sudo dnf upgrade --advisory=FEDORA-2026-994176daf5
Debian 12 · samba · FIXED · 2:4.17.12+dfsg-0+deb12u4
sudo apt update && sudo apt install --only-upgrade samba dpkg --compare-versions "$(dpkg-query -W -f='${Version}' samba)" ge "2:4.17.12+dfsg-0+deb12u4" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · samba · FIXED · 2:4.22.8+dfsg-0+deb13u2
sudo apt update && sudo apt install --only-upgrade samba dpkg --compare-versions "$(dpkg-query -W -f='${Version}' samba)" ge "2:4.22.8+dfsg-0+deb13u2" && echo PATCHED || echo STILL-VULNERABLE
RHEL 10 · samba · FIXED · samba-4.23.5-109.el10_2
sudo dnf upgrade --advisory=RHSA-2026:22963 rpm -q samba
RHEL 10.0 Extended Update Support · samba · FIXED · samba-4.21.3-114.el10_0.1
sudo dnf upgrade --advisory=RHSA-2026:28055 rpm -q samba
RHEL 7 Extended Lifecycle Support · samba · FIXED · samba-4.10.16-26.el7_9.1
sudo dnf upgrade --advisory=RHSA-2026:28132 rpm -q samba
RHEL 8 · samba · FIXED · samba-4.19.4-16.el8_10
sudo dnf upgrade --advisory=RHSA-2026:22644 rpm -q samba
RHEL 8.4 Advanced Mission Critical Update Support · samba · FIXED · samba-4.13.3-12.el8_4.1
sudo dnf upgrade --advisory=RHSA-2026:28058 rpm -q samba
Alpine 3.23 · samba · FIXED · samba-4.22.10-r0
apk add --upgrade samba apk info -v samba
Alpine 3.24 · samba · FIXED · samba-4.23.8-r0
apk add --upgrade samba apk info -v samba
Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-1895 · source
sudo dnf update --advisory=ALAS2023-2026-1895
Amazon Linux 2 · see advisory · FIXED · ALAS2-2026-3493 · source
sudo yum update --advisory=ALAS2-2026-3493

Public exploits and detection

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

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-2026-4480?

openshift container platform: downgrade or apply the listed mitigation; samba: upgrade to 4.2.1; enterprise linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-4480 being exploited?

CVE-2026-4480 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-2026-4480 affect?

CVE-2026-4480 affects openshift container platform, samba, enterprise linux. Severity is critical (CVSS 9.0). A flaw was found in the Samba printing subsystem. Samba passes the client-controlled job description string to the command configured with the "print command" setting via the "%J" substitution character without escaping shell meta character

How urgent is CVE-2026-4480?

Priority 71/100. Critical severity; EPSS top 3%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Samba vulnerabilities · Red Hat OpenShift vulnerabilities

Related CVEs

References

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