PatchTheCVECVE-2017-14492: Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash)
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CRITICAL 9.8REMOTEWATCHLISTMITIGATEMITIGATEMITIGATE
CVE-2017-14492 is a critical-severity flaw (CVSS 9.8) affecting ubuntu linux, debian linux, enterprise linux desktop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a crafted IPv6 router advertisement request.
Why this priority
- Critical severity
- EPSS top 1%: 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 | 94.5% (top 1%) |
| CISA exploited list | No |
| Weakness | CWE-119 |
| Published | 2017-10-03 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
canonical ubuntu linux MITIGATE
Affected: 14.04 · 16.04 · 17.04
Fixed in: no fixed release known
Safe to downgrade to: a release before 14.04
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.
debian debian linux MITIGATE
Affected: 7.0 · 7.1 · 9.0
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.
redhat enterprise linux desktop MITIGATE
Affected: 7.0
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.
redhat enterprise linux server MITIGATE
Affected: 7.0
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.
redhat enterprise linux workstation MITIGATE
Affected: 7.0
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.
thekelleys dnsmasq UPGRADE
Affected: <= 2.77
Fixed in: newer than 2.77
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy dnsmasq || rpm -q dnsmasq || dnsmasq --version
2. UPGRADE to newer than 2.77 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade dnsmasq
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade dnsmasq
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
Exact fixes by distribution
A distro patch exists: prefer upgrading over downgrading.
Fedora 46 · shotcut · FIXED · 26.10.30-1.fc46 · FEDORA-2026-7787c7fc2d · source
sudo dnf upgrade --advisory=FEDORA-2026-7787c7fc2d
Debian 12 · dnsmasq · FIXED · 2.78-1
sudo apt update && sudo apt install --only-upgrade dnsmasq
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.78-1" && echo PATCHED || echo STILL-VULNERABLE
Debian 13 · dnsmasq · FIXED · 2.78-1
sudo apt update && sudo apt install --only-upgrade dnsmasq
dpkg --compare-versions "$(dpkg-query -W -f='${Version}' dnsmasq)" ge "2.78-1" && echo PATCHED || echo STILL-VULNERABLE
RHEL 7 · dnsmasq · FIXED · dnsmasq-2.76-2.el7_4.2
sudo dnf upgrade --advisory=RHSA-2017:2836
rpm -q dnsmasq
RHEL 7.2 Extended Update Support · dnsmasq · FIXED · dnsmasq-2.66-14.el7_2.2
sudo dnf upgrade --advisory=RHSA-2017:2837
rpm -q dnsmasq
RHEL 7.3 Extended Update Support · dnsmasq · FIXED · dnsmasq-2.66-21.el7_3.2
sudo dnf upgrade --advisory=RHSA-2017:2837
rpm -q dnsmasq
RHEL 5 · dnsmasq · NOT AFFECTED
RHEL 6 · dnsmasq · NOT AFFECTED
Alpine 3.20 · dnsmasq · FIXED · dnsmasq-2.78-r0
apk add --upgrade dnsmasq
apk info -v dnsmasq
Alpine 3.21 · dnsmasq · FIXED · dnsmasq-2.78-r0
apk add --upgrade dnsmasq
apk info -v dnsmasq
Alpine 3.22 · dnsmasq · FIXED · dnsmasq-2.78-r0
apk add --upgrade dnsmasq
apk info -v dnsmasq
Alpine 3.23 · dnsmasq · FIXED · dnsmasq-2.78-r0
apk add --upgrade dnsmasq
apk info -v dnsmasq
sudo yum update --advisory=ALAS2-2019-1251
sudo yum update --advisory=ALAS-2017-907
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Write-up: security.googleblog.com/2017/10/behind-masq-yet-more-dns-and-dhcp.html
- Write-up: www.exploit-db.com/exploits/42942/
- Exploit-DB: Dnsmasq < 2.78 - Heap Overflow
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.
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-2017-14492?
ubuntu linux: mitigate or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation; enterprise linux desktop: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2017-14492 being exploited?
CVE-2017-14492 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-2017-14492 affect?
CVE-2017-14492 affects ubuntu linux, debian linux, enterprise linux desktop. Severity is critical (CVSS 9.8). Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a crafted IPv6 router advertisement request.
How urgent is CVE-2017-14492?
Priority 74/100. Critical severity; EPSS top 1%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist
Software pages
Ubuntu vulnerabilities · Debian vulnerabilities · Dnsmasq vulnerabilities
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