How severe is CVE-2023-26964?

CVE-2023-26964 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2023-26964 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-26964?

CVE-2023-26964 primarily affects Hyper H2. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-26964?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-26964 published?

CVE-2023-26964 was published on 2023-04-11 and last updated on 2026-06-17.

CVE-2023-26964

CVE-2023-26964 is a high-severity vulnerability in Hyper H2 with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Affected product: Hyper H2
Published: 2023-04-11
Last modified: 2026-06-17

Description

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).

Frequently asked questions

What is 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).
How severe is CVE-2023-26964?: CVE-2023-26964 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2023-26964 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-26964?: CVE-2023-26964 primarily affects Hyper H2. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-26964?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-26964 published?: CVE-2023-26964 was published on 2023-04-11 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:hyper:h2:0.2.4:*:*:*:*:rust:*:*
cpe:2.3:a:hyper:hyper:0.13.7:*:*:*:*:rust:*:*

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