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Fencer Intel
high 7.5

CVE-2018-6337 json

folly::secureRandom will re-use a buffer between parent and child processes when fork() is called.

published 2018-12-31 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-18097

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

folly::secureRandom will re-use a buffer between parent and child processes when fork() is called. That will result in multiple forked children producing repeat (or similar) results. This affects HHVM 3.26 prior to 3.26.3 and the folly library between v2017.12.11.00 and v2018.08.09.00.

Patch / fix

  • facebook hhvm 3.26.3

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

1.78% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

  • Facebook HHVM
  • Facebook folly

Classification

Weakness
  • CWE-212 Improper Removal of Sensitive Information Before Storage or Transfer
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.