CVE-2023-51714Network attack vector

Memory corruption via oversized HPACK headers

Published Dec 24, 2023 · Updated Aug 2, 2024

Integer overflow in affected Qt 5.15 and 6.x HTTP/2 releases allows remote attackers to corrupt memory via oversized headers. HPack entry_size adds header-name and value lengths and narrows the result before checking the limit, allowing wraparound or truncation to bypass the check. The trigger requires more than 4 GiB of total headers or more than 2 GiB in one header pair, exposing internal buffers to overflow.

CVSS severity9.8
Critical
EPSS probability0.98%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer overflow in affected Qt 5.15 and 6.x HTTP/2 releases allows remote attackers to corrupt memory via oversized headers. HPack entry_size adds header-name and value lengths and narrows the result before checking the limit, allowing wraparound or truncation to bypass the check. The trigger requires more than 4 GiB of total headers or more than 2 GiB in one header pair, exposing internal buffers to overflow.

The record

CVE
CVE-2023-51714
Published
Dec 24, 2023
Updated
Aug 2, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-190, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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