CVE-2026-114605: dnspython dns.name.from_wire_parser() excessive CPU use
Impact A maliciously crafted DNS message may cause dns.name.fromwireparser() to use excessive CPU for DNS name decompression. Applications that process untrusted DNS wire form messages with dnspython may be degraded or DoS'd by the extra CPU use required.
Patches This problem is fixed in dnspython 2.9.0.
Workarounds There are no known workarounds.
Credit Evgenios Gkritsis, Department of Informatics, University of Piraeus & Athena Research Center, Greece Constantinos Patsakis, Department of Informatics, University of Piraeus & Athena Research Center, Greece George Stergiopoulos, Department of Informatics, Athens University of Economics and Business, Greece
Other sources
dnspython is a DNS toolkit for Python. Prior to 2.9.0, dns.name.fromwireparser follows attacker-controlled DNS compression pointer chains without a hop limit. A malicious DNS wire-format message can force excessive pointer traversal during name decompression, causing high CPU use, application degradation, or denial of service in applications that process untrusted DNS messages. This issue is fixed in version 2.9.0.
— Ubuntu
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
pip/dnspythonto a version that resolves this vulnerability.Fixed in 2.9.0 - Upgrade
Upgrade
debian/dnspythonto a version that resolves this vulnerability.Fixed in 2.8.0-7 - Upgrade
Upgrade
dnspythonto a version that resolves this vulnerability.Fixed in 2.9.0
Event History
Frequently Asked Questions
Which applications are exposed to this issue?
Applications using dnspython versions before 2.9.0 are exposed if they process untrusted DNS wire-format messages through dns.name.from_wire_parser().
What does an attacker need to exploit the vulnerability?
An attacker needs to provide a malicious DNS wire-format message containing compression pointer chains. No privileges or user interaction are required.
How can I determine whether my deployment is affected?
Check the installed dnspython version and identify whether the application processes untrusted DNS messages. Versions prior to 2.9.0 are affected in that usage scenario.
What is the available fix?
Upgrade dnspython to version 2.9.0, which adds a hop limit for DNS compression pointer traversal.