CVE-2024-25617Network attack vector

Service interruption via oversized header canonicalization

Published Feb 14, 2024 · Updated Feb 13, 2025

Denial of service in Squid before 6.5 allows remote attackers to exhaust memory or stall transactions via oversized HTTP headers. Header-list canonicalization can expand received values beyond the 65,535-byte String limit; getList then throws after processReplyHeader allocates a reply, leaking memory, while related paths assert or stall. Default header-size limits leave versions 3.0 through 6.4 exposed; configurations below 21 KB avoid the vulnerable state.

CVSS severity8.6
High
EPSS probability88.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Squid before 6.5 allows remote attackers to exhaust memory or stall transactions via oversized HTTP headers. Header-list canonicalization can expand received values beyond the 65,535-byte String limit; getList then throws after processReplyHeader allocates a reply, leaking memory, while related paths assert or stall. Default header-size limits leave versions 3.0 through 6.4 exposed; configurations below 21 KB avoid the vulnerable state.

The record

CVE
CVE-2024-25617
Published
Feb 14, 2024
Updated
Feb 13, 2025
Vendor
The Squid Software Foundation
Product
Squid
Classifications
CWE-182, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 14, 2024CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 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=0 <6.5
  2. Affected versionversion=< 6.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Squid Software Foundation · Squidversion=0 <6.5; version=< 6.5

Published CVSS scores

8.6GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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-182Collapse of Data into Unsafe Value
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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