Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2018-6335

25
FAUCET Score

CVE-2018-6335 describes a denial-of-service vulnerability in HHVM versions 3.25.2, 3.24.6, and 3.21.10 and below, specifically when the proxygen server handles HTTP/2 requests. A malformed HTTP/2 frame can trigger a 'std::out_of_range' exception during priority metadata parsing, leading to service disruption. This vulnerability carries a CVSS v3 score of 7.5 (HIGH), indicating it can be exploited remotely with low complexity and no user interaction, resulting in high availability impact. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 3.21.10CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*
3.24.6CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:3.24.6:*:*:*:*:*:*:*
3.25.2CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:3.25.2:*:*:*:*:*:*:*
< 3.21.11CPE match
cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.5HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
1.47%
Probability of exploitation in next 30 days
EPSS Percentile
71.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0147 is in the 52nd percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / facebook/hhvm/commit/4cb57dd753a339654ca464c139db9871fe961d56
PatchThird Party Advisory
hhvm.com / blog/2018/05/04/hhvm-3.25.3.html
Vendor Advisory