CVE-2018-16855: powerdns recursor Out-of-bounds Read
Vulnerability summary
CVE-2018-16855 is a high (CVSS 7.5) Out-of-bounds Read vulnerability in powerdns recursor. EPSS estimates a 58.58% chance of exploitation in the next 30 days, higher than 99.1% of scored vulnerabilities.
Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 59% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 4 · Related 3Timeline
- 03-12-2018PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
6 scores · 5 sources · 2 versions- NVDNIST7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
58.58%
Chance of exploitation in the next 30 days
Percentile
99%
Versus all other CVEs
30-day change
No change 0.00 pp
From 58.58% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
[unknown]1 product
- pdns-recursor4.1.8
Alpine1 product
- pdns-recursor< 4.1.8-r0
Debian1 product
- pdns-recursor< 4.1.8-1
Powerdns1 product
- recursor< 4.1.8
Ubuntu1 product
- pdns-recursorAll versions (No fix recorded)
5 vendors · 5 products
References
7 links- bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16855X Refsource CONFIRMIssue TrackingThird Party Advisory
- docs.powerdns.com/recursor/security-advisories/powerdns-advisory-2018-09.htmlX Refsource MISCVendor Advisory
