CVE-2026-42304
Description
Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.4.0rc2, the twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server. This vulnerability is fixed in 26.4.0rc2.
How to fix
- twisted twisted26.4.0 or later
- twisted26.4.0rc2, 26.4.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| twisted twisted | v < 26.4.0, 26.4.0 | 26.4.0 |
| twistedPyPI | v < 26.4.0rc2, v < 26.4.0 | 26.4.0rc2, 26.4.0 |
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