How severe is CVE-2018-20102?

CVE-2018-20102 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-2018-20102 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20102?

CVE-2018-20102 primarily affects Haproxy. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-20102?

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-2018-20102 published?

CVE-2018-20102 was published on 2018-12-12 and last updated on 2026-06-17.

CVE-2018-20102

CVE-2018-20102 is a high-severity vulnerability in Haproxy 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: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Haproxy
Published: 2018-12-12
Last modified: 2026-06-17

Description

An out-of-bounds read in dns_validate_dns_response in dns.c was discovered in HAProxy through 1.8.14. Due to a missing check when validating DNS responses, remote attackers might be able read the 16 bytes corresponding to an AAAA record from the non-initialized part of the buffer, possibly accessing anything that was left on the stack, or even past the end of the 8193-byte buffer, depending on the value of accepted_payload_size.

Frequently asked questions

What is CVE-2018-20102?: An out-of-bounds read in dns_validate_dns_response in dns.c was discovered in HAProxy through 1.8.14. Due to a missing check when validating DNS responses, remote attackers might be able read the 16 bytes corresponding to an AAAA record from the non-initialized part of the buffer, possibly accessing anything that was left on the stack, or even past the end of the 8193-byte buffer, depending on the value of accepted_payload_size.
How severe is CVE-2018-20102?: CVE-2018-20102 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-2018-20102 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20102?: CVE-2018-20102 primarily affects Haproxy. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-20102?: 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-2018-20102 published?: CVE-2018-20102 was published on 2018-12-12 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*
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:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openshift_container_platform:3.11:*:*:*:*:*:*:*

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