Is CVE-2026-42304 in the CISA KEV catalog?

No. CVE-2026-42304 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-42304?

CVE-2026-42304 has a CVSS v3 base score of 7.5 (Important).

What is the EPSS score for CVE-2026-42304?

CVE-2026-42304 has an EPSS score of 0.43% (35th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-42304?

Upgrade twisted on debian unstable to 26.4.0-1 or later. Fixes are available for 3 affected products.

CVE & CISA-KEV Catalog

CVE-2026-42304

HIGH

7.5

CVSS v3

NVD

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.

CWE-400Resource Exhaustion CWE-407

How to fix

Remediation Available

twistedDebian

Fixed in:26.4.0-1CVE-2026-42304

python3-twistedUbuntu

Fixed in:22.1.0-2ubuntu2.7USN-8380-1

Fixed in:24.3.0-1ubuntu0.2USN-8380-1

Fixed in:24.11.0-1ubuntu0.1USN-8380-1

twistedUbuntu

Fixed in:22.1.0-2ubuntu2.7USN-8380-1

Fixed in:24.3.0-1ubuntu0.2USN-8380-1

Fixed in:24.11.0-1ubuntu0.1USN-8380-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.43%probability of exploitation in 30 days

35thpercentile

Low risk: more likely to be exploited than 35% of all known CVEs.

References

Exploit1

github.com

Related Vulnerabilities

Other CWE-400 (Resource Exhaustion) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-44487	High	7.5	100%	KEV	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2011-3192	High	7.8	99%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2024-25617	Medium	5.3	89%	-	Fix
CVE-2018-1000115	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-19.