5.9

CVE-2026-42387: powerdns recursor Improper Input Validation

CVSS: 5.9v3.1MediumDeferred
AliasesUBUNTU-CVE-2026-42387DEBIAN-CVE-2026-42387
Published 25-06-2026Last modified 25-06-2026
Open JSON

Vulnerability summary

CVE-2026-42387 is a medium (CVSS 5.9) Improper Input Validation vulnerability in powerdns recursor. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 40.6% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.48%
0%100%
Low · +0.10 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 25-06-2026
    PublishedVulnerability first disclosed.
  2. 25-06-2026
    Last modifiedVulnerability information updated.

Description

A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.48%

Chance of exploitation in the next 30 days

Percentile

41%

Versus all other CVEs

30-day change

+0.10 pp

From 0.39% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.48%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • pdns-recursorAll versions (No fix recorded) | < 5.2.11-0+deb13u1 | < 5.4.3-1
Powerdns1 product
  • recursor≥ 5.2.0, < 5.2.11 | ≥ 5.3.0, < 5.3.8 | ≥ 5.4.0, < 5.4.3
Ubuntu1 product
  • pdns-recursorAll versions (No fix recorded)

3 vendors · 3 products

References

5 links