How severe is CVE-2018-20679?

CVE-2018-20679 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2018-20679 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20679?

CVE-2018-20679 primarily affects Busybox. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-20679?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-20679 published?

CVE-2018-20679 was published on 2019-01-09 and last updated on 2026-06-17.

CVE-2018-20679

CVE-2018-20679 is a high-severity vulnerability in Busybox with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 8% (94th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Busybox
Published: 2019-01-09
Last modified: 2026-06-17

Description

An issue was discovered in BusyBox before 1.30.0. An out of bounds read in udhcp components (consumed by the DHCP server, client, and relay) allows a remote attacker to leak sensitive information from the stack by sending a crafted DHCP message. This is related to verification in udhcp_get_option() in networking/udhcp/common.c that 4-byte options are indeed 4 bytes.

Frequently asked questions

What is CVE-2018-20679?: An issue was discovered in BusyBox before 1.30.0. An out of bounds read in udhcp components (consumed by the DHCP server, client, and relay) allows a remote attacker to leak sensitive information from the stack by sending a crafted DHCP message. This is related to verification in udhcp_get_option() in networking/udhcp/common.c that 4-byte options are indeed 4 bytes.
How severe is CVE-2018-20679?: CVE-2018-20679 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2018-20679 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20679?: CVE-2018-20679 primarily affects Busybox. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-20679?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-20679 published?: CVE-2018-20679 was published on 2019-01-09 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:busybox:busybox:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*

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