What is CVE-2018-16855?

CVE-2018-16855 is a high-severity vulnerability in Powerdns Recursor, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2018-12-03.

How severe is CVE-2018-16855?

High severity. CVSS v3 base score is 7.5 out of 10.

Out-of-bounds Read in Powerdns Recursor

CVE-2018-16855

An issue has been found in PowerDNS Recursor before version 4.1.8 where a remote attacker sending a DNS query can trigger an out-of-bounds memory read while computing the hash of the query for a packet cache lookup, possibly leading to a crash.

Vulnerability class: Buffer Overflow

Published 2018-12-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.586 (99.1th percentile), scored 2026-10-19.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.586 · newest: 0.586 · change: 0.000

Affected products

Powerdns Recursor
[Unknown] Pdns-Recursor — versions 4.1.8

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2018-09.html (Vendor Advisory)

Frequently asked questions

What is CVE-2018-16855?: CVE-2018-16855 is a high-severity vulnerability in Powerdns Recursor, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2018-12-03.
How severe is CVE-2018-16855?: High severity. CVSS v3 base score is 7.5 out of 10.