Security readout for executives and security teams
Plain-English summary
Some versions of HHVM and Facebook Folly could generate repeated random values after a process forks. If those values protect tokens, identifiers, or other trust decisions, duplicates can undermine integrity. The source bundle names fixed HHVM 3.26.3 and a Folly fix commit, but does not show active exploitation.
Executive priority
Treat as high priority where HHVM or Folly supports authentication, session, token, or workflow integrity. For organizations without those components, urgency is lower. Because active exploitation is not evidenced in the supplied sources, prioritize exposure confirmation and patching over incident escalation.
Technical view
folly::secureRandom reuses a buffer between parent and child processes when fork() is called, so forked children may produce repeated or similar results. Affected ranges are HHVM 3.26 before 3.26.3 and Folly between v2017.12.11.00 and v2018.08.09.00. CVSS 3.1 is 7.5 with high integrity impact.
Likely exposure
Exposure is likely in services using HHVM 3.26 before 3.26.3 or applications embedding vulnerable Folly releases, especially fork-based worker services relying on folly::secureRandom for security-sensitive randomness. Systems not using HHVM or Folly are not indicated as affected by the provided sources.
Exploitation context
The source bundle does not cite known public exploitation, and KEV status is false. Practical risk depends on whether repeated random output influences security decisions such as tokens, nonces, identifiers, or authorization workflows. The provided sources do not describe exploit procedures or observed attacks.
Researcher notes
The key exposure question is whether affected code paths call folly::secureRandom in forked child processes and then use the output for security-sensitive integrity decisions. Evidence is limited to the CVE description, HHVM 3.26.3 release reference, and upstream commits; no broader affected-product list is provided.
Mitigation direction
- Upgrade HHVM 3.26 deployments to 3.26.3 or later vendor-fixed builds.
- Update Folly outside the vulnerable v2017.12.11.00 to v2018.08.09.00 range.
- Prioritize services that fork workers and use Folly randomness in trust decisions.
- Check current vendor guidance before choosing compensating controls or backports.
Validation and detection
- Inventory HHVM versions across production, CI images, and deploy artifacts.
- Inventory direct and transitive Folly versions in application builds.
- Identify fork-based services that call folly::secureRandom after process creation.
- Review whether random outputs protect tokens, nonces, identifiers, or authorization logic.
- Confirm patched builds include the referenced HHVM or Folly fixes.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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Open ATT&CK lookupCVE-2018-6337 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://hhvm.com/blog/2018/05/24/hhvm-3.26.3.htmlCVE reference · x_refsource_MISC
- https://github.com/facebook/folly/commit/8e927ee48b114c8a2f90d0cbd5ac753795a6761fCVE reference · x_refsource_MISC
- https://github.com/facebook/hhvm/commit/e2d10a1e32d01f71aaadd81169bcb9ae86c5d6b8CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Removal of Sensitive Information Before Storage or Transfer
Improper Removal of Sensitive Information Before Storage or Transfer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.