CVE-2018-6340

mediumpriority · track · 33EPSS 0.014 · 73 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.43% (73rd) EPSS

CVSS 6.8 · medium

Is it mine?

6 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

The Memcache::getextendedstats function can be used to trigger an out-of-bounds read. Exploiting this issue requires control over memcached server hostnames and/or ports. This affects all supported versions of HHVM (3.30 and 3.27.4 and below).

cvss

Technical severity, 0–10. One row per scoring source.

8.1

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.8–8.1

v2.06.8mediumAV:N/AC:M/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 6.4

v3.08.1highCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.2 · impact 5.9

v3.18.1highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.18.1highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondaryexploitability 2.2 · impact 5.9

v3.17.4highCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-125USprimary

affected products (6)

Products and version ranges known to be affected.

Facebook HHVM≤ 3.27.5enisa_euvdEU
Facebook HHVM≤ 3.30.1enisa_euvdEU
Facebook HHVM3.30.0 → unspecifiedenisa_euvdEU
Facebook HHVMunspecified → 3.27.5enisa_euvdEU
facebook hhvm≤ 3.27.4nvdUScpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*
facebook hhvm= 3.30nvdUScpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2018-12-31modified 2026-06-17

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+11869 more

references (6)

External citations — patches, advisories, analysis.

scry

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