# CVE-2026-128089: dnspython excessive memory and CPU use

Status: published. Published: 2026-11-13. Updated: 2026-11-13.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- rthalley / dnspython: < 2.9.2 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- 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; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-400, CWE-770

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/rthalley/dnspython/security/advisories/GHSA-vvf4-9x63-8xvv (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/rthalley/dnspython/commit/388db14ee9923288f6e73f86e482c77706e59d73 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rthalley/dnspython/commit/a62e1be066da0ed71b5b59f37435bb17cfa0070f (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/rthalley/dnspython/releases/tag/v2.9.2 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-128089; retrieved 2026-11-13; source updated 2026-11-13

Revision: 967b7d72e541cd9579d6a19d0307319e51cea7e4ea3706cdd94722661b86132c

Canonical: https://y2.dev/cve/CVE-2026-128089

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