CVE-2017-12987: The IEEE 802.11 parser in tcpdump before 4.9.2 has a buffer over-read in print-802_11.c:parse_elements().

Q: How do I fix CVE-2017-12987?

tcpdump: upgrade to newer than 4.9.1; 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.

Q: Is CVE-2017-12987 being exploited?

CVE-2017-12987 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-2017-12987 affect?

CVE-2017-12987 affects tcpdump, debian linux, enterprise linux desktop. Severity is critical (CVSS 9.8). The IEEE 802.11 parser in tcpdump before 4.9.2 has a buffer over-read in print-802_11.c:parse_elements().

Q: How urgent is CVE-2017-12987?

Priority 66/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADEMITIGATEMITIGATE

CVE-2017-12987 is a critical-severity flaw (CVSS 9.8) affecting tcpdump, debian linux, enterprise linux desktop. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The IEEE 802.11 parser in tcpdump before 4.9.2 has a buffer over-read in print-802_11.c:parse_elements().

Why this priority

Critical severity
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	3.3% (top 12%)
CISA exploited list	No
Weakness	CWE-125
Published	2017-09-14
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · redhat · 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.

debian debian linux MITIGATE

Affected: 9.0 · 10.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

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 server aus MITIGATE

Affected: 7.6 · 7.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.6

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.

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-2017-12987?

tcpdump: upgrade to newer than 4.9.1; 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-2017-12987 being exploited?

CVE-2017-12987 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-2017-12987 affect?

CVE-2017-12987 affects tcpdump, debian linux, enterprise linux desktop. Severity is critical (CVSS 9.8). The IEEE 802.11 parser in tcpdump before 4.9.2 has a buffer over-read in print-802_11.c:parse_elements().

How urgent is CVE-2017-12987?

Priority 66/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

Related CVEs

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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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