7.5

CVE-2018-6335: facebook hhvm Uncontrolled Resource Consumption

CVSS: 7.5v3.1HighModified
AliasesUBUNTU-CVE-2018-6335
Published 31-12-2018Last modified 06-05-2025
Open JSON

Vulnerability summary

CVE-2018-6335 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in facebook hhvm. EPSS estimates a 1.47% chance of exploitation in the next 30 days, higher than 73.3% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
1.47%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 31-12-2018
    PublishedVulnerability first disclosed.
  2. 06-05-2025
    Last modifiedVulnerability information updated.

Description

A Malformed h2 frame can cause 'std::out_of_range' exception when parsing priority meta data. This behavior can lead to denial-of-service. This affects all supported versions of HHVM (3.25.2, 3.24.6, and 3.21.10 and below) when using the proxygen server to handle HTTP2 requests.

CVSS metrics

6 scores · 3 sources · 3 versions

EPSS trend

Probability

1.47%

Chance of exploitation in the next 30 days

Percentile

73%

Versus all other CVEs

30-day change

0.00 pp

From 1.47% on 20-09-2026

20-09-202620-10-2026
EPSS score
1.47%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Facebook1 product
  • hhvm3.25.3 | 3.25.0 | 3.24.7 | 3.22.0 | 3.21.11 | ≥ unspecified, < 3.21.11 | ≤ 3.21.10 | 3.24.6 | 3.25.2
Ubuntu1 product
  • hhvmAll versions (No fix recorded)

2 vendors · 2 products

References

4 links