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01 Record

CVE-2018-6332

A potential denial-of-service issue in the Proxygen handling of invalid HTTP2 settings which can cause the server to spend disproportionate resources. This affects all supported versions of HHVM

MediumPUBLISHEDCNA: facebook
CNA base score5.9 CVSS v3.xCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

02 Description

A potential denial-of-service issue in the Proxygen handling of invalid HTTP2 settings which can cause the server to spend disproportionate resources. This affects all supported versions of HHVM

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
1.08% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 64.9% of scored records. A rank, not a probability.
NVD base score
5.9 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2018-12-03 14:00Z7 YR AGO
Last updated
2025-05-06 19:01Z1 YR AGO
Reserved
2018-01-26
Assigning CNA
facebook
Record state
PUBLISHED
Severity
Medium (CVSS 5.9)
CNA CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
Data version
5.1
Document digest
85d256c96a1e341c42157f6af0e080a5b73db9b6e9474043c905ff9bd4c68793

05 Affected products

VendorProductVersionsPlatforms
FacebookHHVM3.24.4, 3.22.0 to < unspecified, 3.21.8, < 3.21.8—

06 References

07 Fixed in

Ubuntu 16.04 LTS

  • hhvm
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • hhvm
    No fix yet

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.