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Fencer Vulns
high 7.5

CVE-2023-26964 json

h2 vulnerable to denial of service

published 2023-04-11 3 y ago modified 2026-06-17 4 mo ago also GHSA-f8vr-r385-rh5r , RUSTSEC-2023-0034 , EUVD-2023-1284

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

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).

Patch / fix

  • crates.io h2 0.3.17
  • rust-h2 Debian 14, Debian 13, Debian 12 0.3.13-2

debian advisories DEBIAN-CVE-2023-26964

  • sccache SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Development Tools 15 SP7 0.16.0~0-150600.10.11.1
  • rust-keylime SLE Micro 5.5 0.2.7+141-150500.3.5.1
  • rust-keylime SLE Micro 5.4 0.2.7+141-150400.3.5.1
  • rust-keylime SLE Micro 5.3 0.2.7+141-150400.3.7.1
  • rustup SLE Module for Development Tools 15 SP5, SLE Module for Development Tools 15 SP4, openSUSE Leap 15.5 +1 more 1.26.0~0-150400.3.7.1

suse advisories SUSE-SU-2026:3022-1SUSE-SU-2025:02811-1SUSE-SU-2025:02810-1SUSE-SU-2025:02809-1SUSE-SU-2023:2603-1

  • mdbook openSUSE Tumbleweed 0.5.4-1.1
  • kanidm Package Hub 15 SP6, openSUSE Leap 15.6 1.3.3~git0.f075d13-bp156.4.1
  • rustup openSUSE Tumbleweed 1.25.2~0-4.1
  • sccache openSUSE Tumbleweed 0.4.1~18-2.1
  • wasm-pack openSUSE Tumbleweed 0.11.0~0-2.1
  • watchexec openSUSE Tumbleweed 1.22.3-1.1
  • pijul openSUSE Tumbleweed 1.0.0~beta.5-1.1
  • hoard openSUSE Tumbleweed v.1.4.2~0-1.1

opensuse advisories openSUSE-SU-2026:12402-1openSUSE-SU-2024:0294-1openSUSE-SU-2024:12861-1openSUSE-SU-2024:12862-1openSUSE-SU-2024:12864-1openSUSE-SU-2024:12960-1

  • rpm-ostree CBL-Mariner 2.0 2022.1-7
  • kata-containers CBL-Mariner 2.0 3.2.0.azl0-1
  • kata-containers Azure Linux 3.0 3.2.0.azl0-2
  • rpm-ostree Azure Linux 3.0 2024.4-1
  • rust Azure Linux 3.0 h2-0.3.26

azure linux advisories AZL-26291AZL-26730AZL-34823AZL-35217AZL-61174

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-26964 updated cvss 3.7

rust-hyper: Stream stacking occurs when H2 processes HTTP2 RST_STREAM frames

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
20 mo ago

Exploit prediction

1.12% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/hyperium/hyper/issues/2877 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
crates.io h2
<0.3.17
>=0.0.0-0, <0.3.17
0.3.17

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.