CVE-2022-31394Public exploitNetwork attack vector

Service interruption via excessive HTTP/2 header buffering

Published Feb 21, 2023 · Updated Mar 17, 2025

Resource exhaustion in Hyper before 0.14.19 allows remote attackers to interrupt HTTP/2 services with oversized header sequences. The HTTP/2 server path inherits h2's 16 MiB header-list limit but exposes no max_header_list_size setting, so long chains of 10 KiB CONTINUATION frames consume excessive memory. An unauthenticated client that can reach a Hyper-based HTTP/2 server can repeat the sequence across connections until the hosting service runs out of memory.

CVSS severity7.5
High
EPSS probability1.08%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Hyper before 0.14.19 allows remote attackers to interrupt HTTP/2 services with oversized header sequences. The HTTP/2 server path inherits h2's 16 MiB header-list limit but exposes no max_header_list_size setting, so long chains of 10 KiB CONTINUATION frames consume excessive memory. An unauthenticated client that can reach a Hyper-based HTTP/2 server can repeat the sequence across connections until the hosting service runs out of memory.

The record

CVE
CVE-2022-31394
Published
Feb 21, 2023
Updated
Mar 17, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-770, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.002Service Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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