CVE-2019-13951: The set_ipv4() function in zscan_rfc1035.rl in gdnsd 3.x before 3.2.1 has a stack-based buffer overflow via a

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2019-13951 is a critical-severity flaw (CVSS 9.8) affecting gdnsd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The set_ipv4() function in zscan_rfc1035.rl in gdnsd 3.x before 3.2.1 has a stack-based buffer overflow via a long and malformed IPv4 address in zone data.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.7% (top 23%)
CISA exploited list	No
Weakness	CWE-787
Published	2019-07-18
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: gdnsd

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

Am I affected?

Timeline

2019-07-18 17:15 UTCPublished CVE record published
2026-06-17 02:17 UTCUpdated Record last modified

gdnsd gdnsd DOWNGRADE

Affected: 3.2.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.2.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.2.0 (Debian / Ubuntu)

apt-cache madison gdnsd sudo apt install gdnsd=<VERSION_BEFORE_3.2.0> sudo apt-mark hold gdnsd

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list gdnsd sudo dnf downgrade gdnsd-<VERSION_BEFORE_3.2.0> sudo dnf versionlock add gdnsd

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.

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-2019-13951?

gdnsd: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2019-13951 being exploited?

CVE-2019-13951 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-2019-13951 affect?

CVE-2019-13951 affects gdnsd. Severity is critical (CVSS 9.8). The set_ipv4() function in zscan_rfc1035.rl in gdnsd 3.x before 3.2.1 has a stack-based buffer overflow via a long and malformed IPv4 address in zone data.

How urgent is CVE-2019-13951?

Priority 64/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2019-13952 CRITICAL 9.8 UPGRADE The set_ipv6() function in zscan_rfc1035.rl in gdnsd before 2.4.3 and 3.x before 3.2.1 has a stack-based buffe

References

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