The try_read_command function in memcached.c in memcached before 1.4.39 allows remote attackers to cause a denial of service (segmentation fault) via a request to add/set a key, which makes a comparison between signed and unsigned int and triggers a heap-based buffer over-read. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-8705.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2017-9951 from the MITRE CVE dictionary dictionary and NIST NVD.
Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 5.3 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | None |
| Integrity Impact | None |
| Availability Impact | Low |
| Platform | Package | State |
|---|---|---|
| Red Hat OpenStack Platform 9.0 | memcached | Will not fix |
| Red Hat OpenStack Platform 8.0 (Liberty) | memcached | Will not fix |
| Red Hat OpenStack Platform 12.0 | memcached | Not affected |
| Red Hat OpenStack Platform 11.0 (Ocata) | memcached | Will not fix |
| Red Hat OpenStack Platform 10 | memcached | Will not fix |
| Red Hat Mobile Application Platform On-Premise 4 | memcached | Will not fix |
| Red Hat Enterprise Linux OpenStack Platform 7.0 (Kilo) for RHEL 7 | memcached | Will not fix |
| Red Hat Enterprise Linux 7 | memcached | Will not fix |
| Red Hat Enterprise Linux 6 | memcached | Will not fix |
This flaw is in the memcached binary protocol. If your client programs only use the ASCII protocol when communicating with memcached, you can disable the binary protocol and protect against this flaw by adding "-B ascii" to OPTIONS in /etc/sysconfig/memcached.
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