CVE-2023-46846Network attack vector

Security-control bypass via lenient chunked decoding

Published Nov 3, 2023 · Updated Feb 25, 2026

HTTP request smuggling in Squid 2.6 through 6.3 allows remote attackers to bypass frontend security via crafted chunked messages. The TeChunkedParser accepts 0x-prefixed chunk sizes and non-CRLF boundaries that peer servers can parse differently. Exploitation requires HTTP/1.1 or ICAP chunked encoding and an upstream server whose interpretation differs from Squid's.

CVSS severity9.3
Critical
EPSS probability6.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP request smuggling in Squid 2.6 through 6.3 allows remote attackers to bypass frontend security via crafted chunked messages. The TeChunkedParser accepts 0x-prefixed chunk sizes and non-CRLF boundaries that peer servers can parse differently. Exploitation requires HTTP/1.1 or ICAP chunked encoding and an upstream server whose interpretation differs from Squid's.

The record

CVE
CVE-2023-46846
Published
Nov 3, 2023
Updated
Feb 25, 2026
Vendor
Red Hat
Product
Red Hat Enterprise Linux 6
Classifications
CWE-444, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 3, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Red Hat · Red Hat Enterprise Linux 6Affected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 9.0 Extended Update SupportAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.2 Advanced Update SupportAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.2 Telecommunications Update ServiceAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.2 Update Services for SAP SolutionsAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.4 Telecommunications Update ServiceAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 7 Extended Lifecycle SupportAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.6 Extended Update SupportAffected versions are unavailable in this record.
The Squid Software Foundation · Squidversion=2.6 <6.4
Red Hat · Red Hat Enterprise Linux 8.1 Update Services for SAP SolutionsAffected versions are unavailable in this record.
Red Hat · Red Hat Enterprise Linux 8.4 Update Services for SAP SolutionsAffected versions are unavailable in this record.

Published CVSS scores

9.3The Squid Software FoundationCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
5.3NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
T1190Exploit Public-Facing Application

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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