High severity · published Mar 31, 2026
CVE-2026-27853
Out-of-bounds write when rewriting large DNS packets
7.5
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DN
DNSdist · PowerDNS
1.9.0 before 1.9.12; 2.0.0 before 2.0.3 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27853
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-27853
Vendor Advisory
https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-02.html
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