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CVE-2026-128089 dnspython excessive memory and CPU use

7.5 highFix available

High (7.5) in rthalley dnspython. Fixed in dnspython 2.9.2.

On this page
dnspython is a DNS toolkit for Python. Prior to version 2.9.2, the from_text() parser for WKS records does not require the service number to be between 0 and 65535 before using it as a bitmap offset. An attacker-controlled zone file can supply a larger number, causing the service bitmap to grow to an extremely large size through inefficient repeated extension, consuming excessive memory and CPU and potentially terminating the process. Applications are affected only when they parse zone-file text whose record type and rdata are attacker controlled. This issue is fixed in version 2.9.2.

Severity

CVSS 3.1

7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWEs
CWE-400 Uncontrolled Resource Consumption
CWE-770 Allocation of Resources Without Limits or Throttling
Published
Assigned by
GitHub_M (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
rthalley dnspython< 2.9.2

Fix and patched versions

  • dnspython (PyPI): fixed in 2.9.2

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-vvf4-9x63-8xvvPyPIdnspython<2.9.22.9.2

Attack patterns (CAPEC)

  • CAPEC-147 XML Ping of the Death Likelihood: Low · Severity: Medium
  • CAPEC-227 Sustained Client Engagement
  • CAPEC-492 Regular Expression Exponential Blowup

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits. More on the page of CWE-770 (20).

References

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