CVE-2026-83813 (CVSS 3.1)

Description

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.names.dns.DNSDatagramProtocol accepts a UDP DNS response for a pending query when its 16-bit transaction ID matches but does not verify that the response came from the queried host and port. An attacker able to deliver a packet to the resolver's listening port with the correct transaction ID can inject a forged answer. The standard twisted.names.client.Resolver uses a new random source port for each query, increasing off-path attack complexity, while applications that reuse a DNSDatagramProtocol instance expose only the transaction-ID search space after the first query. A successful forgery can redirect hostname resolution and enable mail interception, server-side request forgery, or man-in-the-middle positioning. This issue is fixed in version 26.10.0rc1.

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CVSS v3.1 Score

3.1

LOW

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

Weakness Type (CWE)

CWE-346 CWE-346

References

Other References

https://github.com/twisted/twisted/commit/b53e1c3477c209b5609a1c74cf9e48373b5879ac https://github.com/twisted/twisted/pull/12700 https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1 https://github.com/twisted/twisted/security/advisories/GHSA-jj36-9pvh-vj5r

Frequently Asked Questions

What is CVE-2026-83813? +

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.names.dns.DNSDatagramProtocol accepts a UDP DNS response for a pending query when its 16-bit transaction ID matches but does not verify that the response came from the queried host and port. An attacker able to deliver a packet to the resolver's listening port with the correct transaction ID can inject a forged answer. The standard twisted.names.client.Resolver uses a new random source port for each query, increasing off-path attack complexity, while applications that reuse a DNSDatagramProtocol instance expose only the transaction-ID search space after the first query. A successful forgery can redirect hostname resolution and enable mail interception, server-side request forgery, or man-in-the-middle positioning. This issue is fixed in version 26.10.0rc1. It has a CVSS v3.1 base score of 3.1 (LOW).

How severe is CVE-2026-83813? +

CVE-2026-83813 has a CVSS v3.1 score of 3.1 out of 10, rated LOW. This is a low-severity vulnerability with limited impact.

How do I check if I'm vulnerable to CVE-2026-83813? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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