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VulnerabilityPublished

CVE-2026-27853: PowerDNS DNSdist · Out-of-bounds Write

Affects PowerDNS DNSdistSource CVE Database V5

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Not known to be exploited · CVSS 5.9 Medium : upgrade to 2.0.3 or 1.9.12 when convenient.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.0.3, 1.9.12
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 31 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade DNSdist and dnsdist to 2.0.3 or 1.9.12.

Affected software

ProductAffectedFixed in
PowerDNSDNSdistAffected
  • >=2.0.0 <2.0.3
Fixed in
  • 2.0.3
PowerDNSDNSdistAffected
  • >=1.9.0 <1.9.12
Fixed in
  • 1.9.12
GitHubdnsdistpkg:github/dnsdistOther threatsAffected
  • >=1.9.0 <1.9.12
  • >=2.0.0 <2.0.3
Fixed in
  • 1.9.12
  • 2.0.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-27853, organizations should upgrade affected DNSdist instances to patched versions once available from PowerDNS. If you cannot patch yet, administrators should audit and restrict the use of Lua scripting, especially the DNSQuestion:changeName and DNSResponse:changeName methods, to trusted scripts only. Implement strict input validation and size checks within Lua scripts to prevent packet size expansion beyond protocol limits. Network-level controls such as filtering or rate limiting suspicious DNS responses can reduce exposure. Monitoring DNSdist logs for crashes or unusual DNS response patterns can aid early detection. Additionally, deploying redundant DNS infrastructure and failover mechanisms can minimize service disruption in case of exploitation. Regularly reviewing and updating DNSdist configurations and applying security best practices for DNS services will further reduce risk.

Description

An attacker might be able to trigger an out-of-bounds write by sending crafted DNS responses to a DNSdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code. In some cases the rewritten packet might become larger than the initial response and even exceed 65535 bytes, potentially leading to a crash resulting in denial of service.

References

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