CVE-2017-9951 — The try_read_command function in memcached

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. N

01What is this vulnerability?

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.

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

08Timeline

• Published: 2017-07-17T13:18:30.970
• Last modified: 2026-05-13T00:24:29.033

09References

• www.securityfocus.com — http://www.securityfocus.com/bid/99874
• github.com — https://github.com/memcached/memcached/wiki/ReleaseNotes1439
• groups.google.com — https://groups.google.com/forum/message/raw?msg=memcached/ubGWrkmrr4E/nrm1SeVJAQ…
• usn.ubuntu.com — https://usn.ubuntu.com/3588-1/
• www.debian.org — https://www.debian.org/security/2018/dsa-4218
• www.twistlock.com — https://www.twistlock.com/2017/07/13/cve-2017-9951-heap-overflow-memcached-serve…
• www.securityfocus.com — http://www.securityfocus.com/bid/99874
• github.com — https://github.com/memcached/memcached/wiki/ReleaseNotes1439
• groups.google.com — https://groups.google.com/forum/message/raw?msg=memcached/ubGWrkmrr4E/nrm1SeVJAQ…
• usn.ubuntu.com — https://usn.ubuntu.com/3588-1/