CVE-2023-6193Public exploitNetwork attack vector

Memory exhaustion via unbounded PATH_RESPONSE queue

Published Dec 12, 2023 · Updated Aug 2, 2024

Uncontrolled resource consumption in Cloudflare quiche 0.15.0 through 0.19.0 allows remote attackers to exhaust server memory. Connection path handling queues one PATH_RESPONSE for each received PATH_CHALLENGE without bounding the pending queue when responses cannot be sent. No authentication is required; sustained challenge traffic plus congestion-window or acknowledgment manipulation can exhaust memory and interrupt the hosting service.

CVSS severity5.3
Medium
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in Cloudflare quiche 0.15.0 through 0.19.0 allows remote attackers to exhaust server memory. Connection path handling queues one PATH_RESPONSE for each received PATH_CHALLENGE without bounding the pending queue when responses cannot be sent. No authentication is required; sustained challenge traffic plus congestion-window or acknowledgment manipulation can exhaust memory and interrupt the hosting service.

The record

CVE
CVE-2023-6193
Published
Dec 12, 2023
Updated
Aug 2, 2024
Vendor
Cloudflare
Product
quiche
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 12, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.15.0 <=0.19.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cloudflare · quicheversion=0.15.0 <=0.19.0

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
5.3CloudflareCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

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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