PT-2018-1907

CVE-2018-1000027

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Published

2018-01-29

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Updated

2026-10-31

Description by

CVSS 3.1
7.5
High
MetricsAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Name of the Vulnerable Software and Affected Versions Squid HTTP Caching Proxy versions prior to 4.0.23
Description The issue is related to a NULL Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing. This can result in Denial of Service to all clients of the proxy. The attack appears to be exploitable via a remote HTTP server responding with an X-Forwarded-For header to certain types of HTTP requests. Additionally, there is an issue with buffer overflow when processing ESI responses or loading intermediate certificate authority certificates, which can also lead to a Denial of Service.
Recommendations For Squid HTTP Caching Proxy versions prior to 4.0.23, update to version 4.0.23 or later to resolve the issue. As a temporary workaround, consider restricting access to the X-Forwarded-For header in HTTP responses until the update is applied.
Exploitability
Exploit
Fix
Impacts
Vendors
Affected products
Related identifiers
ALT-PU-2018-2314
CESA-2020_1068
CLEANSTART-2025-EN68234
CLSA-2026-1776878817
DLA-1266-1
DLA-1267-1
DSA-4122-1
OPENSUSE-SU-2024:11403-1
RHSA-2020:1068
RHSA-2020_1068
SUSE-SU-2018:0636-1
SUSE-SU-2018:0752-1
USN-3557-1
USN-4059-2
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