How severe is CVE-2018-16855?

CVE-2018-16855 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 none, integrity none, and availability high.

Is CVE-2018-16855 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 59% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-16855?

CVE-2018-16855 affects Powerdns Recursor. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-16855?

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-2018-16855 published?

CVE-2018-16855 was published on 2018-12-03 and last updated on 2026-06-17.

CVE-2018-16855

CVE-2018-16855 is a high-severity vulnerability in Powerdns Recursor with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 59% places it in the 99th percentile, indicating an elevated likelihood of exploitation. 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: 59% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Powerdns Recursor
Published: 2018-12-03
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2018-16855?: CVE-2018-16855 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 none, integrity none, and availability high.
Is CVE-2018-16855 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 59% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-16855?: CVE-2018-16855 affects Powerdns Recursor. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-16855?: 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-2018-16855 published?: CVE-2018-16855 was published on 2018-12-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:powerdns:recursor:*:*:*:*:*:*:*:*

More vulnerabilities in Powerdns Recursor

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CVE-2025-59023 — High (CVSS 8.2): Crafted delegations or IP fragments can poison cached delegations in Recursor.
CVE-2019-3806 — High (CVSS 8.1): An issue has been found in PowerDNS Recursor versions after 4.1.3 before 4.1.9 where Lua hooks are not properly applied…
CVE-2015-5470 — High (CVSS 7.8): The label decompression functionality in PowerDNS Recursor before 3.6.4 and 3.7.x before 3.7.3 and Authoritative (Auth)…
CVE-2015-1868 — High (CVSS 7.8): The label decompression functionality in PowerDNS Recursor 3.5.x, 3.6.x before 3.6.3, and 3.7.x before 3.7.2 and…

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Other CWE-125 (Out-of-bounds Read) vulnerabilities

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CVE-2024-22004 — Critical (CVSS 10.0): Due to length check, an attacker with privilege access on a Linux Nonsecure operating system can trigger a…
CVE-2021-41556 — Critical (CVSS 10.0): sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that…
CVE-2021-21777 — Critical (CVSS 10.0): An information disclosure vulnerability exists in the Ethernet/IP UDP handler functionality of EIP Stack Group OpENer…
CVE-2017-14451 — Critical (CVSS 10.0): An exploitable out-of-bounds read vulnerability exists in libevm (Ethereum Virtual Machine) of CPP-Ethereum. A…
CVE-2013-0767 — Critical (CVSS 10.0): The nsSVGPathElement::GetPathLengthScale function in Mozilla Firefox before 18.0, Firefox ESR 10.x before 10.0.12 and…

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