Vulnerability Description
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the browser cache and any downstream caches with content from an arbitrary source. Squid uses a string search instead of parsing the Transfer-Encoding header to find chunked encoding. This allows an attacker to hide a second request inside Transfer-Encoding: it is interpreted by Squid as chunked and split out into a second request delivered upstream. Squid will then deliver two distinct responses to the client, corrupting any downstream caches.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Squid-Cache | Squid | < 4.13 |
| Canonical | Ubuntu Linux | 16.04 |
| Debian | Debian Linux | 9.0 |
| Fedoraproject | Fedora | 31 |
| Opensuse | Leap | 15.1 |
Related Weaknesses (CWE)
References
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00012.htmlMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00017.htmlMailing ListThird Party Advisory
- https://github.com/squid-cache/squid/security/advisories/GHSA-c7p8-xqhm-49wvPatch
- https://lists.debian.org/debian-lts-announce/2020/10/msg00005.htmlMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproMailing ListThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproMailing ListThird Party Advisory
- https://security.netapp.com/advisory/ntap-20210219-0007/Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210226-0006/Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210226-0007/Broken LinkThird Party Advisory
- https://usn.ubuntu.com/4477-1/Third Party Advisory
- https://usn.ubuntu.com/4551-1/Third Party Advisory
- https://www.debian.org/security/2020/dsa-4751Mailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00012.htmlMailing ListThird Party Advisory
- http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00017.htmlMailing ListThird Party Advisory
FAQ
What is CVE-2020-15811?
CVE-2020-15811 is a vulnerability with a CVSS score of 6.5 (MEDIUM). An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache pois...
How severe is CVE-2020-15811?
CVE-2020-15811 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2020-15811?
Check the references section above for vendor advisories and patch information. Affected products include: Squid-Cache Squid, Canonical Ubuntu Linux, Debian Debian Linux, Fedoraproject Fedora, Opensuse Leap.