CVE-2024-39702Network attack vector

Proxy denial of service via hash collisions

Published Jul 23, 2024 · Updated Nov 26, 2024

Hash denial of service in OpenResty 1.19.3.1 through 1.25.3.1 allows remote attackers to exhaust resources via crafted proxy requests. The lj_str_hash.c string-interning path uses an optimized CRC32-based hash for short strings, enabling attacker-chosen collisions to drive excessive hash-table work. A relatively small request volume can severely degrade proxy performance, but the flaw is limited to the OpenResty LuaJIT branch on SSE 4.2 builds.

CVSS severity5.9
Medium
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hash denial of service in OpenResty 1.19.3.1 through 1.25.3.1 allows remote attackers to exhaust resources via crafted proxy requests. The lj_str_hash.c string-interning path uses an optimized CRC32-based hash for short strings, enabling attacker-chosen collisions to drive excessive hash-table work. A relatively small request volume can severely degrade proxy performance, but the flaw is limited to the OpenResty LuaJIT branch on SSE 4.2 builds.

The record

CVE
CVE-2024-39702
Published
Jul 23, 2024
Updated
Nov 26, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-407, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 23, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 26, 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

5.9CISA ADPCVSS:3.1/AV:N/AC:H/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-407Inefficient Algorithmic Complexity
T1499.004Application 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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