CVE-2018-16855
HighAn 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.
Published Dec 3, 2018 · Updated Aug 7, 2026 · Also known as DEBIAN-CVE-2018-16855, UBUNTU-CVE-2018-16855
Key Facts
Patch immediately- CVE-2018-16855 is a high-severity vulnerability (CVSS 7.5 v3.1) affecting Recursor (Powerdns), powerdns-recursor (arch), pdns-recursor (alpine).
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 59% probability of exploitation in the next 30 days.
- Fixed versions are available, including pdns-recursor 4.1.2-bp150.2.3.1, pdns-recursor 4.1.2-lp150.2.3.1, pdns-recursor 4.1.8-1.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3.1
7.5
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (30-day exploit likelihood)
59%
Higher than 99.0% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
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Description
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.
Affected Products
37 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| RecursorPowerdns | See advisory | 4.1.8 |
| powerdns-recursorarch | See advisory | 4.1.8-1 |
| pdns-recursoralpine | >= 4.1.8 | 4.1.8-r0 |
Patched Releases
pdns-recursor
4.1.2-bp150.2.3.1, 4.1.2-lp150.2.3.1, 4.1.8-1, 4.1.8-13.1, 4.1.8-r0, 4.5.5-1.3
powerdns-recursor
4.1.8, 4.1.8-1
Timeline
Publicly disclosed
Dec 3, 2018
Last updated
Aug 7, 2026
Weakness Type
- CWE-125 Out-of-bounds Read
References
- advisoryhttps://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16855
- advisoryhttps://doc.powerdns.com/recursor/security-advisories/powerdns-advisory-2018-09.html
- advisoryhttps://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2018-09.html
- advisoryhttps://security-tracker.debian.org/tracker/CVE-2018-16855
- advisoryhttps://ubuntu.com/security/CVE-2018-16855
FAQ
Common Questions.
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.
Affected: Recursor (Powerdns); powerdns-recursor (arch); pdns-recursor (alpine) versions >= 4.1.8. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including pdns-recursor 4.1.2-bp150.2.3.1, pdns-recursor 4.1.2-lp150.2.3.1, pdns-recursor 4.1.8-1.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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