Is CVE-2026-19033 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-19033 being exploited in the wild.

How severe is CVE-2026-19033?

Medium severity, with a CVSS score of 6.5, published 16 September 2026.

Which products and versions are affected?

Isc Bind 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, 9.20.9-S1 through 9.20.27-S1.

Is there a fix for CVE-2026-19033?

A patch was published on 2026-09-16: Fixes released in BIND 9.20.29 and 9.21.26 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-19033 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-19033?

Check whether you run Isc Bind at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-19033: ISC BIND named TSIG signature validation bypass in zone transfers

CVE-2026-19033 · Severity: medium · CVSS 6.5 · Published 2026-09-16

BIND is a widely-used DNS server software that powers authoritative and recursive nameservers. This vulnerability allows an attacker to inject unauthorized DNS zone data into secondary DNS servers protected by TSIG (transaction signature), bypassing the intended security mechanism. An attacker without valid credentials could poison DNS records served to clients, leading to traffic redirection, phishing attacks, or service disruption.

Technologies: Isc Bind. Vendors: Isc.

Quick answers

Is CVE-2026-19033 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-19033 being exploited in the wild.
How severe is CVE-2026-19033?: Medium severity, with a CVSS score of 6.5, published 16 September 2026.
Which products and versions are affected?: Isc Bind 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, 9.20.9-S1 through 9.20.27-S1.
Is there a fix for CVE-2026-19033?: A patch was published on 2026-09-16: Fixes released in BIND 9.20.29 and 9.21.26 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-19033 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-19033?: Check whether you run Isc Bind at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in BIND's handling of multi-message TCP incremental zone transfers (IXFR) when TSIG authentication is enabled. The `named` daemon begins serving zone data from an incoming transfer before validating the final TSIG signature that should authenticate the entire transfer. An attacker can initiate a multi-message IXFR without possessing a valid TSIG key and cause the secondary server to accept and serve the attacker's zone contents; even when the final TSIG signature never arrives, the server does not rollback to its previous state. The vulnerability requires network access to the secondary DNS server and the ability to initiate TCP zone transfers. Patches are available in BIND 9.20.29, 9.21.26, and respective security update branches.

Affected products

ISC BIND 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, 9.20.9-S1 through 9.20.27-S1

Timeline

2026-09-16: disclosed: Vulnerability published by ISC
2026-09-16: patched: Fixes released in BIND 9.20.29 and 9.21.26

References

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