CVE-2005-4890: There is a possible tty hijacking in shadow 4.x before 4.1.5 and sudo 1.x before 1.7.4 via "su - user -c progr

Q: How do I fix CVE-2005-4890?

shadow: upgrade to newer than 4.1.5; sudo: upgrade to newer than 1.7.4; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2005-4890 being exploited?

CVE-2005-4890 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-2005-4890 affect?

CVE-2005-4890 affects shadow, sudo, debian linux. Severity is high (CVSS 7.8). There is a possible tty hijacking in shadow 4.x before 4.1.5 and sudo 1.x before 1.7.4 via "su - user -c program". The user session can be escaped to the parent session by using the TIOCSTI ioctl to push characters into the input buffer to

Q: How urgent is CVE-2005-4890?

Priority 50/100. High severity; Public exploit reference; On your watchlist

This month

HIGH 7.8WATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2005-4890 is a high-severity flaw (CVSS 7.8) affecting shadow, sudo, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

There is a possible tty hijacking in shadow 4.x before 4.1.5 and sudo 1.x before 1.7.4 via "su - user -c program". The user session can be escaped to the parent session by using the TIOCSTI ioctl to push characters into the input buffer to be read by the next process.

Why this priority

High severity
Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-20
Published	2019-11-04
Last modified	2026-06-16

Publisher (CNA): Red Hat, Inc. · Vendor: debian · redhat · sudo project

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-11-04 19:15 UTCPublished CVE record published
2026-06-16 22:19 UTCUpdated Record last modified

debian shadow UPGRADE

Affected: >= 4.0.0 and <= 4.1.5

Fixed in: newer than 4.1.5

Safe to downgrade to: a release before 4.0.0

1. Check installed version

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

2. UPGRADE to newer than 4.1.5 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade shadow

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 4.0.0 (Debian / Ubuntu)

apt-cache madison shadow sudo apt install shadow=<VERSION_BEFORE_4.0.0> sudo apt-mark hold shadow

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list shadow sudo dnf downgrade shadow-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add shadow

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.

sudo project sudo UPGRADE

Affected: >= 1.3.0 and <= 1.7.4

Fixed in: newer than 1.7.4

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 1.7.4 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade sudo

Note

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

debian debian linux MITIGATE

Affected: 8.0 · 9.0 · 10.0

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.

redhat enterprise linux MITIGATE

Affected: 4 · 5 · 6.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4

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-2005-4890?

shadow: upgrade to newer than 4.1.5; sudo: upgrade to newer than 1.7.4; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2005-4890 being exploited?

CVE-2005-4890 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-2005-4890 affect?

CVE-2005-4890 affects shadow, sudo, debian linux. Severity is high (CVSS 7.8). There is a possible tty hijacking in shadow 4.x before 4.1.5 and sudo 1.x before 1.7.4 via "su - user -c program". The user session can be escaped to the parent session by using the TIOCSTI ioctl to push characters into the input buffer to

How urgent is CVE-2005-4890?

Priority 50/100. High severity; Public exploit reference; On your watchlist

Software pages

Debian vulnerabilities · Sudo vulnerabilities

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References

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