CVE-2018-1000027: canonical ubuntu_linux NULL Pointer Dereference
Vulnerability summary
CVE-2018-1000027 is a high (CVSS 7.5) NULL Pointer Dereference vulnerability in canonical ubuntu_linux. EPSS estimates a 12.91% chance of exploitation in the next 30 days, higher than 96.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 7 · Related 4Timeline
- 09-02-2018PublishedVulnerability first disclosed.
- 05-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
12.91%
Chance of exploitation in the next 30 days
Percentile
96%
Versus all other CVEs
30-day change
0.00 pp
From 12.91% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian2 products
- squid< 4.1-1 | < 2.7.STABLE9-4.1+deb7u3
- debian_linuxEOL7.0 | 8.0 | 9.0
Alpine1 product
- squid< 3.5.27-r2 | < 3.5.27-r0
Canonical1 product
- ubuntu_linuxEOL14.04 | 16.04 | 17.10
Squid-cache1 product
- squid< 4.0.23
Ubuntu1 product
- squid3< 3.3.8-1ubuntu6.11 | < 3.5.12-1ubuntu7.5 | < 3.5.23-5ubuntu2
5 vendors · 6 products
References
15 links- www.squid-cache.org/Versions/v4/changesets/SQUID-2018_2.patchX Refsource CONFIRMPatchVendor Advisory
- lists.debian.org/debian-lts-announce/2018/02/msg00001.htmlMailing ListX Refsource MLISTThird Party Advisory
- www.squid-cache.org/Versions/v3/3.5/changesets/SQUID-2018_2.patchX Refsource CONFIRMPatchVendor Advisory
- lists.debian.org/debian-lts-announce/2018/02/msg00002.htmlMailing ListX Refsource MLISTThird Party Advisory