| Name | CVE-2018-1000027 | 
| Description | The Squid Software Foundation Squid HTTP Caching Proxy version prior to version 4.0.23 contains a NULL Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing that can result in Denial of Service to all clients of the proxy. This attack appear to be exploitable via Remote HTTP server responding with an X-Forwarded-For header to certain types of HTTP request. This vulnerability appears to have been fixed in 4.0.23 and later. | 
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) | 
| References | DLA-1266-1, DLA-1267-1, DSA-4122-1 | 
| Debian Bugs | 888720 | 
The table below lists information on source packages.
| Source Package | Release | Version | Status | 
|---|---|---|---|
| squid (PTS) | bullseye | 4.13-10+deb11u3 | fixed | 
| bullseye (security) | 4.13-10+deb11u5 | fixed | |
| bookworm | 5.7-2+deb12u3 | fixed | |
| bookworm (security) | 5.7-2+deb12u4 | fixed | |
| trixie | 6.13-2 | fixed | |
| trixie (security) | 6.13-2+deb13u1 | fixed | |
| forky, sid | 7.2-2 | fixed | 
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs | 
|---|---|---|---|---|---|---|
| squid | source | experimental | 4.0.23-1~exp8 | |||
| squid | source | wheezy | 2.7.STABLE9-4.1+deb7u3 | DLA-1267-1 | ||
| squid | source | (unstable) | 4.1-1 | |||
| squid3 | source | wheezy | 3.1.20-2.2+deb7u8 | DLA-1266-1 | ||
| squid3 | source | jessie | 3.4.8-6+deb8u5 | DSA-4122-1 | ||
| squid3 | source | stretch | 3.5.23-5+deb9u1 | DSA-4122-1 | ||
| squid3 | source | (unstable) | 3.5.27-1 | 888720 | 
src:squid as source package reintroduced for 4.x in experimental
Squid 3.5: http://www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2018_2.patch
Squid 4: http://www.squid-cache.org/Versions/v4/changesets/SQUID-2018_2.patch
http://www.squid-cache.org/Advisories/SQUID-2018_2.txt