CVE-2026-88975 Http4s - Denial of Service

Http4s prior to 0.23.37 and 1.0.0-M48 contains a denial of service caused by improper HTTP/2 frame size validation in Ember's read loop, letting unauthenticated peers cause memory amplification, exploit requires network access.

CVSS base score 7.5 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.63% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Denial of Service
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
15 September 2026
Updated
15 October 2026
Weakness
CWE-400

Vendor fix

Update to versions 0.23.37 or 1.0.0-M48 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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