CVE-2018-19519: In tcpdump 4.9.2, a stack-based buffer over-read exists in the print_prefix function of print-hncp.c via craft

This month

MEDIUM 5.5DOWNGRADE

CVE-2018-19519 is a medium-severity flaw (CVSS 5.5) affecting tcpdump. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In tcpdump 4.9.2, a stack-based buffer over-read exists in the print_prefix function of print-hncp.c via crafted packet data because of missing initialization.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.6% (top 15%)
CISA exploited list	No
Weakness	CWE-125, CWE-909
Published	2018-11-25
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: tcpdump

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

Am I affected?

Timeline

2018-11-25 20:29 UTCPublished CVE record published
2026-06-17 01:49 UTCUpdated Record last modified

tcpdump tcpdump DOWNGRADE

Affected: 4.9.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.9.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 4.9.2 (Debian / Ubuntu)

apt-cache madison tcpdump sudo apt install tcpdump=<VERSION_BEFORE_4.9.2> sudo apt-mark hold tcpdump

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

dnf --showduplicates list tcpdump sudo dnf downgrade tcpdump-<VERSION_BEFORE_4.9.2> sudo dnf versionlock add tcpdump

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-2018-19519?

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

Is CVE-2018-19519 being exploited?

CVE-2018-19519 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-2018-19519 affect?

CVE-2018-19519 affects tcpdump. Severity is medium (CVSS 5.5). In tcpdump 4.9.2, a stack-based buffer over-read exists in the print_prefix function of print-hncp.c via crafted packet data because of missing initialization.

How urgent is CVE-2018-19519?

Priority 46/100. Public exploit reference

Related CVEs

CVE-2018-16301 HIGH 7.8 UPGRADE The command-line argument parser in tcpdump before 4.99.0 has a buffer overflow in tcpdump.c:read_infile()
CVE-1999-1024 HIGH 7.5 DOWNGRADE ip_print procedure in Tcpdump 3.4a allows remote attackers to cause a denial of service via a packet with a ze
CVE-2000-1026 HIGH 10.0 DOWNGRADE Multiple buffer overflows in LBNL tcpdump allow remote attackers to execute arbitrary commands.
CVE-2023-1801 MEDIUM 6.5 DOWNGRADE The SMB protocol decoder in tcpdump version 4.99.3 can perform an out-of-bounds write when decoding a crafted
CVE-2020-8037 HIGH 7.5 DOWNGRADE MITIGATE The ppp decapsulator in tcpdump 4.9.3 can be convinced to allocate a large amount of memory.

References

← Back to latest CVEs