CVE-2017-12997: The LLDP parser in tcpdump before 4.9.2 could enter an infinite loop due to a bug in print-lldp.c:lldp_private

Q: How do I fix CVE-2017-12997?

tcpdump: upgrade to newer than 4.9.1. Exact commands for each OS are on this page.

Q: Is CVE-2017-12997 being exploited?

CVE-2017-12997 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-2017-12997 affect?

CVE-2017-12997 affects tcpdump. Severity is critical (CVSS 9.8). The LLDP parser in tcpdump before 4.9.2 could enter an infinite loop due to a bug in print-lldp.c:lldp_private_8021_print().

Q: How urgent is CVE-2017-12997?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2017-12997 is a critical-severity flaw (CVSS 9.8) affecting tcpdump. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The LLDP parser in tcpdump before 4.9.2 could enter an infinite loop due to a bug in print-lldp.c:lldp_private_8021_print().

Why this priority

Critical severity
Remotely exploitable, no login, no user action

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	2.5% (top 16%)
CISA exploited list	No
Weakness	CWE-835, CWE-125
Published	2017-09-14
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

2017-09-14 06:29 UTCPublished CVE record published
2026-06-17 01:04 UTCUpdated Record last modified

tcpdump tcpdump UPGRADE

Affected: <= 4.9.1

Fixed in: newer than 4.9.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 4.9.1 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tcpdump

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2017-12997?

tcpdump: upgrade to newer than 4.9.1. Exact commands for each OS are on this page.

Is CVE-2017-12997 being exploited?

CVE-2017-12997 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-2017-12997 affect?

CVE-2017-12997 affects tcpdump. Severity is critical (CVSS 9.8). The LLDP parser in tcpdump before 4.9.2 could enter an infinite loop due to a bug in print-lldp.c:lldp_private_8021_print().

How urgent is CVE-2017-12997?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

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

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