NULL pointer dereference in Squid-Cache Squid

CVE-2018-1000027

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.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.129 (96.2th percentile), scored .

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 96.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2018-1000027: held from 0.129 to 0.129.

EPSS over last 30 days · oldest: 0.129 · newest: 0.129 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2018-1000027?
CVE-2018-1000027 is a high-severity vulnerability in Squid-Cache Squid, classified under NULL Pointer Dereference. CVSS score: 7.5/10. Published 2018-02-09.
How severe is CVE-2018-1000027?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2018-1000027 known to be exploited?
3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.