CVE-2024-45802Public exploitNetwork attack vector

Proxy service interruption via malformed ESI responses

Published Oct 28, 2024 · Updated Nov 3, 2025

Input validation flaws in Squid 3.0 through 6.9 allow remote attackers controlling trusted origin servers to interrupt service via ESI responses. During ESI tag interpretation, inconsistent type handling, invalid resource lifetimes, and unreleased resources trigger assertions, null dereferences, use-after-free crashes, or memory exhaustion. Exposure requires Squid to act as a reverse proxy with ESI enabled at build time; a malicious trusted-origin response disrupts every domain and client served by that proxy.

CVSS severity7.5
High
EPSS probability47.88%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Input validation flaws in Squid 3.0 through 6.9 allow remote attackers controlling trusted origin servers to interrupt service via ESI responses. During ESI tag interpretation, inconsistent type handling, invalid resource lifetimes, and unreleased resources trigger assertions, null dereferences, use-after-free crashes, or memory exhaustion. Exposure requires Squid to act as a reverse proxy with ESI enabled at build time; a malicious trusted-origin response disrupts every domain and client served by that proxy.

The record

CVE
CVE-2024-45802
Published
Oct 28, 2024
Updated
Nov 3, 2025
Vendor
The Squid Software Foundation
Product
Squid
Classifications
CWE-20, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 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?

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

  1. Affected versionversion=>= 3.0, < 6.10
  2. Affected versionversion=3.0 <6.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Squid Software Foundation · Squidversion=>= 3.0, < 6.10; version=3.0 <6.10

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Red HatCVSS: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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
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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