What is CVE-2023-26964?

CVE-2023-26964 is a high-severity vulnerability in Hyper H2, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2023-04-11.

How severe is CVE-2023-26964?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Hyper H2

CVE-2023-26964

An issue was discovered in hyper v0.13.7. h2-0.2.4 Stream stacking occurs when the H2 component processes HTTP2 RST_STREAM frames. As a result, the memory and CPU usage are high which can lead to a Denial of Service (DoS).

Published 2023-04-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.011 (64.9th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 64.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Hyper H2 — versions 0.2.4
Hyper — versions 0.13.7

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

github.com/hyperium/hyper/issues/2877 (Exploit, Issue Tracking)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)

Frequently asked questions

What is CVE-2023-26964?: CVE-2023-26964 is a high-severity vulnerability in Hyper H2, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2023-04-11.
How severe is CVE-2023-26964?: High severity. CVSS v3 base score is 7.5 out of 10.