PatchTheCVECVE-2017-14491: Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash)
74
This week
CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE
CVE-2017-14491 is a critical-severity flaw (CVSS 9.8) affecting dnsmasq, enterprise linux desktop, enterprise linux server. 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 DNS response.
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 | 86.5% (top 1%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2017-10-04 |
| 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
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.
redhat enterprise linux desktop MITIGATE
Affected: 6.0 · 7.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 6.0
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: 6.0 · 7.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 6.0
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: 6.0 · 7.0
Fixed in: no fixed release known
Safe to downgrade to: a release before 6.0
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.
canonical ubuntu linux MITIGATE
Affected: 12.04 · 14.04 · 16.04 · 17.04
Fixed in: no fixed release known
Safe to downgrade to: a release before 12.04
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 · 8.0 · 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.
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 5.9 Long Life · dnsmasq · FIXED · dnsmasq-2.45-2.el5_9.1
sudo dnf upgrade --advisory=RHSA-2017:2841
rpm -q dnsmasq
RHEL 5 Extended Lifecycle Support · dnsmasq · FIXED · dnsmasq-2.45-2.el5_11.1
sudo dnf upgrade --advisory=RHSA-2017:2840
rpm -q dnsmasq
RHEL 6 · dnsmasq · FIXED · dnsmasq-2.48-18.el6_9
sudo dnf upgrade --advisory=RHSA-2017:2838
rpm -q dnsmasq
RHEL 6.2 Advanced Update Support · dnsmasq · FIXED · dnsmasq-2.48-5.el6_2.2
sudo dnf upgrade --advisory=RHSA-2017:2839
rpm -q dnsmasq
RHEL 6.4 Advanced Update Support · dnsmasq · FIXED · dnsmasq-2.48-13.el6_4.1
sudo dnf upgrade --advisory=RHSA-2017:2839
rpm -q dnsmasq
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.
- GitHub PoC: skyformat99/dnsmasq-2.4.1-fix-CVE-2017-14491 (0 stars)
- Write-up: security.googleblog.com/2017/10/behind-masq-yet-more-dns-and-dhcp.html
- Write-up: www.exploit-db.com/exploits/42941/
- Exploit-DB: Dnsmasq < 2.78 - 2-byte 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-2017-14491?
dnsmasq: upgrade to newer than 2.77; enterprise linux desktop: mitigate or apply the listed mitigation; enterprise linux server: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2017-14491 being exploited?
CVE-2017-14491 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-2017-14491 affect?
CVE-2017-14491 affects dnsmasq, enterprise linux desktop, enterprise linux server. 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 DNS response.
How urgent is CVE-2017-14491?
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
Related CVEs
- CVE-2026-12725 MEDIUM 5.9 UPGRADE MITIGATE A heap-based buffer overflow was found in dnsmasq
- CVE-2026-12969 MEDIUM 5.3 MITIGATE UPGRADE An out-of-bounds read vulnerability exists in dnsmasq's find_soa() function in src/rfc1035.c
- CVE-2023-49441 HIGH 7.5 DOWNGRADE dnsmasq 2.9 is vulnerable to Integer Overflow via forward_query.
- CVE-2023-28450 HIGH 7.5 UPGRADE An issue was discovered in Dnsmasq before 2.90
- CVE-2022-0934 HIGH 7.5 UPGRADE MITIGATE A single-byte, non-arbitrary write/use-after-free flaw was found in dnsmasq