CVE-2022-39028: telnetd in GNU Inetutils through 2.3, MIT krb5-appl through 1.0.3, and derivative works has a NULL pointer der

Q: How do I fix CVE-2022-39028?

inetutils: upgrade to newer than 2.3; kerberos 5: upgrade to newer than 1.0.3; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2022-39028 being exploited?

CVE-2022-39028 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-2022-39028 affect?

CVE-2022-39028 affects inetutils, kerberos 5, debian linux. Severity is high (CVSS 7.5). telnetd in GNU Inetutils through 2.3, MIT krb5-appl through 1.0.3, and derivative works has a NULL pointer dereference via 0xff 0xf7 or 0xff 0xf8. In a typical installation, the telnetd application would crash but the telnet service would r

Q: How urgent is CVE-2022-39028?

Priority 62/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

HIGH 7.5REMOTEWATCHLISTUPGRADEUPGRADEMITIGATE

CVE-2022-39028 is a high-severity flaw (CVSS 7.5) affecting inetutils, kerberos 5, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

telnetd in GNU Inetutils through 2.3, MIT krb5-appl through 1.0.3, and derivative works has a NULL pointer dereference via 0xff 0xf7 or 0xff 0xf8. In a typical installation, the telnetd application would crash but the telnet service would remain available through inetd. However, if the telnetd application has many crashes within a short time interval, the telnet service would become unavailable after inetd logs a "telnet/tcp server failing (loopi

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.3% (top 16%)
CISA exploited list	No
Weakness	CWE-476
Published	2022-08-30
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · gnu · mit · netkit-telnet project

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

Am I affected?

Timeline

2022-08-30 05:15 UTCPublished CVE record published
2026-06-17 04:57 UTCUpdated Record last modified

gnu inetutils UPGRADE

Affected: <= 2.3

Fixed in: newer than 2.3

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 2.3 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade inetutils

Note

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

mit kerberos 5 UPGRADE

Affected: <= 1.0.3

Fixed in: newer than 1.0.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy kerberos-5 || rpm -q kerberos-5 || kerberos-5 --version

2. UPGRADE to newer than 1.0.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade kerberos-5

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade kerberos-5

Note

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

debian debian linux MITIGATE

Affected: 10.0

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.

netkit-telnet project netkit-telnet UPGRADE

Affected: <= 0.17

Fixed in: newer than 0.17

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy netkit-telnet || rpm -q netkit-telnet || netkit-telnet --version

2. UPGRADE to newer than 0.17 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade netkit-telnet

Note

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

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-2022-39028?

inetutils: upgrade to newer than 2.3; kerberos 5: upgrade to newer than 1.0.3; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2022-39028 being exploited?

CVE-2022-39028 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-2022-39028 affect?

CVE-2022-39028 affects inetutils, kerberos 5, debian linux. Severity is high (CVSS 7.5). telnetd in GNU Inetutils through 2.3, MIT krb5-appl through 1.0.3, and derivative works has a NULL pointer dereference via 0xff 0xf7 or 0xff 0xf8. In a typical installation, the telnetd application would crash but the telnet service would r

How urgent is CVE-2022-39028?

Priority 62/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

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References

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