CVE-2026-33596 PUBLISHED

TCP backend stream ID overflow

Assigner: OX
Reserved: 23.03.2026 Published: 22.04.2026 Updated: 22.04.2026

A client might theoretically be able to cause a mismatch between queries sent to a backend and the received responses by sending a flood of perfectly timed queries that are routed to a TCP-only or DNS over TLS backend.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS Score: 3.1

Attack Vector	Adjacent Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	Low

CVSS 3.1

Product Status

Vendor	PowerDNS
Product	DNSdist
Versions	Default: unaffected affected from 1.9.0 to 1.9.13 (excl.) affected from 2.0.0 to 2.0.4 (excl.)

Credits

ylwango613 finder

References

https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-04.html

Problem Types

Integer Overflow or Wraparound CWE