CVE-2011-1930: In klibc 1.5.20 and 1.5.21, the DHCP options written by ipconfig to /tmp/net-$DEVICE.conf are not properly esc

Q: How do I fix CVE-2011-1930?

klibc: upgrade to 1.5.25; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2011-1930 being exploited?

CVE-2011-1930 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-2011-1930 affect?

CVE-2011-1930 affects klibc, debian linux. Severity is critical (CVSS 9.8). In klibc 1.5.20 and 1.5.21, the DHCP options written by ipconfig to /tmp/net-$DEVICE.conf are not properly escaped. This may allow a remote attacker to send a specially crafted DHCP reply which could execute arbitrary code with the privileg

Q: How urgent is CVE-2011-1930?

Priority 74/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATE

CVE-2011-1930 is a critical-severity flaw (CVSS 9.8) affecting klibc, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In klibc 1.5.20 and 1.5.21, the DHCP options written by ipconfig to /tmp/net-$DEVICE.conf are not properly escaped. This may allow a remote attacker to send a specially crafted DHCP reply which could execute arbitrary code with the privileges of any process which sources DHCP options.

Why this priority

Critical severity
EPSS top 2%: 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 score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	20.5% (top 2%)
CISA exploited list	No
Published	2019-11-14
Last modified	2026-06-16

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

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

Am I affected?

Timeline

2019-11-14 03:15 UTCPublished CVE record published
2026-06-16 23:30 UTCUpdated Record last modified

klibc project klibc UPGRADE

Affected: < 1.5.25

Fixed in: 1.5.25

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 1.5.25 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade klibc

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.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · keepalived · FIXED · 2.4.3-1.fc46 · FEDORA-2026-0c83a077d7 · source

sudo dnf upgrade --advisory=FEDORA-2026-0c83a077d7

Fedora ELN · dracut · FIXED · 111-5.eln159 · FEDORA-2026-982407d9e3 · source

sudo dnf upgrade --advisory=FEDORA-2026-982407d9e3

Debian 12 · klibc · FIXED · 1.5.22-1

sudo apt update && sudo apt install --only-upgrade klibc dpkg --compare-versions "$(dpkg-query -W -f='${Version}' klibc)" ge "1.5.22-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · klibc · FIXED · 1.5.22-1

sudo apt update && sudo apt install --only-upgrade klibc dpkg --compare-versions "$(dpkg-query -W -f='${Version}' klibc)" ge "1.5.22-1" && 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.

Exploit-DB: klibc 1.5.2 - DHCP Options Processing Remote Shell Command Execution

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-2011-1930?

klibc: upgrade to 1.5.25; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2011-1930 being exploited?

CVE-2011-1930 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-2011-1930 affect?

CVE-2011-1930 affects klibc, debian linux. Severity is critical (CVSS 9.8). In klibc 1.5.20 and 1.5.21, the DHCP options written by ipconfig to /tmp/net-$DEVICE.conf are not properly escaped. This may allow a remote attacker to send a specially crafted DHCP reply which could execute arbitrary code with the privileg

How urgent is CVE-2011-1930?

Priority 74/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

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CVE-2021-31871 HIGH 7.5 UPGRADE MITIGATE An issue was discovered in klibc before 2.0.9
CVE-2021-31870 CRITICAL 9.8 UPGRADE MITIGATE An issue was discovered in klibc before 2.0.9

References

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