CVE-2026-24061: GNU InetUtils Argument Injection Vulnerability

100

Patch now

CRITICAL 9.8EXPLOITEDREMOTEWATCHLISTUPGRADEMITIGATE

CVE-2026-24061 is a critical-severity flaw (CVSS 9.8) affecting inetutils, debian linux, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER environment variable.

Why this priority

Critical severity
EPSS top 1%: very likely to be exploited
Exploited in the wild (CISA KEV)
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	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	99.0% (top 1%)
CISA exploited list	Yes, fix due 2026-02-16
Weakness	CWE-88
Published	2026-01-21
Last modified	2026-09-30

Publisher (CNA): MITRE · Vendor: debian · gnu

Last updated 2026-09-30 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-01-21 07:16 UTCPublished CVE record published
2026-01-26Exploited Added to the CISA Known Exploited Vulnerabilities list
2026-02-16Deadline CISA due date for US federal agencies to patch
2026-09-30 11:47 UTCUpdated Record last modified

gnu inetutils UPGRADE

Affected: >= 1.9.3 and <= 2.7

Fixed in: newer than 2.7

Safe to downgrade to: a release before 1.9.3

1. Check installed version

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

2. UPGRADE to newer than 2.7 (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.

3. If no update is available yet, DOWNGRADE to a release before 1.9.3 (Debian / Ubuntu)

apt-cache madison inetutils sudo apt install inetutils=<VERSION_BEFORE_1.9.3> sudo apt-mark hold inetutils

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

dnf --showduplicates list inetutils sudo dnf downgrade inetutils-<VERSION_BEFORE_1.9.3> sudo dnf versionlock add inetutils

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.

debian debian linux MITIGATE

Affected: 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0

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 46 · proftpd · FIXED · 1.3.9e-2.fc46 · FEDORA-2026-fcb0a25c2f · source

sudo dnf upgrade --advisory=FEDORA-2026-fcb0a25c2f

Ubuntu 22.04 · inetutils · FIXED · 2:2.2-2ubuntu0.2

sudo apt update && sudo apt install --only-upgrade inetutils dpkg --compare-versions "$(dpkg-query -W -f='${Version}' inetutils)" ge "2:2.2-2ubuntu0.2" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · inetutils · FIXED · 2:2.5-3ubuntu4.1

sudo apt update && sudo apt install --only-upgrade inetutils dpkg --compare-versions "$(dpkg-query -W -f='${Version}' inetutils)" ge "2:2.5-3ubuntu4.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 25.10 · inetutils · FIXED · 2:2.6-1ubuntu3.1

sudo apt update && sudo apt install --only-upgrade inetutils dpkg --compare-versions "$(dpkg-query -W -f='${Version}' inetutils)" ge "2:2.6-1ubuntu3.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · inetutils · FIXED · 2:1.9.4-11ubuntu0.2+esm3

sudo apt update && sudo apt install --only-upgrade inetutils dpkg --compare-versions "$(dpkg-query -W -f='${Version}' inetutils)" ge "2:1.9.4-11ubuntu0.2+esm3" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · inetutils · FIXED · 2:2.4-2+deb12u2

sudo apt update && sudo apt install --only-upgrade inetutils dpkg --compare-versions "$(dpkg-query -W -f='${Version}' inetutils)" ge "2:2.4-2+deb12u2" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · inetutils · FIXED · 2:2.6-3+deb13u1

sudo apt update && sudo apt install --only-upgrade inetutils dpkg --compare-versions "$(dpkg-query -W -f='${Version}' inetutils)" ge "2:2.6-3+deb13u1" && echo PATCHED || echo STILL-VULNERABLE

Alpine 3.24 · inetutils-telnet · FIXED · inetutils-telnet-2.8-r0

apk add --upgrade inetutils-telnet apk info -v inetutils-telnet

Public exploits and detection

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

GitHub PoC: SafeBreach-Labs/CVE-2026-24061 (209 stars)
GitHub PoC: JayGLXR/CVE-2026-24061-POC (69 stars)
GitHub PoC: ZeroDayEvil/CVE-2026-24061 (22 stars)
Write-up: redteam.ae/blog/cve-2026-24061-inetutils-telnetd-root-bypass
Write-up: www.vicarius.io/vsociety/posts/cve-2026-24061-detection-script-remote-authentication-bypas
Write-up: www.vicarius.io/vsociety/posts/cve-2026-24061-mitigation-script-remote-authentication-bypa
Exploit-DB: GNU InetUtils 2.6 - Telnetd Remote Privilege Escalation
Metasploit: GNU Inetutils Telnet Authentication Bypass Exploit CVE-2026-24061

Verify at the official source NVD · CVE Program · CISA KEV catalog · 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-2026-24061?

inetutils: upgrade to newer than 2.7; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-24061 being exploited?

Yes. CVE-2026-24061 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2026-24061 affect?

CVE-2026-24061 affects inetutils, debian linux. Severity is critical (CVSS 9.8). telnetd in GNU Inetutils through 2.7 allows remote authentication bypass via a "-f root" value for the USER environment variable.

How urgent is CVE-2026-24061?

Priority 100/100. Critical severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

CVE-2026-32772 LOW 3.4 UPGRADE telnet in GNU inetutils through 2.7 allows servers to read arbitrary environment variables from clients via NE
CVE-2026-32746 CRITICAL 9.8 UPGRADE telnetd in GNU inetutils through 2.7 allows an out-of-bounds write in the LINEMODE SLC (Set Local Characters)
CVE-2026-28372 HIGH 7.4 UPGRADE telnetd in GNU inetutils through 2.7 allows privilege escalation that can be exploited by abusing systemd serv
CVE-2023-40303 HIGH 7.8 UPGRADE GNU inetutils before 2.5 may allow privilege escalation because of unchecked return values of set*id() family
CVE-2022-39028 HIGH 7.5 UPGRADE UPGRADE telnetd in GNU Inetutils through 2.3, MIT krb5-appl through 1.0.3, and derivative works has a NULL pointer der

References

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