CVE-2020-1892Network attack vector

Memory disclosure and crash via unchecked JSON depth

Published Mar 3, 2020 · Updated Aug 4, 2024

Out-of-bounds read in affected HHVM 4.x releases allows attackers to read process memory or crash the runtime via JSON decoding. JSON_parser accepts a zero depth for a top-level string and reads stack index -1 instead of rejecting the invalid depth. Reachability requires an application to pass attacker-controlled JSON and a zero depth to json_decode; consequences are bounded to memory disclosure and a runtime crash.

CVSS severity8.1
High
EPSS probability1.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in affected HHVM 4.x releases allows attackers to read process memory or crash the runtime via JSON decoding. JSON_parser accepts a zero depth for a top-level string and reads stack index -1 instead of rejecting the invalid depth. Reachability requires an application to pass attacker-controlled JSON and a zero depth to json_decode; consequences are bounded to memory disclosure and a runtime crash.

The record

CVE
CVE-2020-1892
Published
Mar 3, 2020
Updated
Aug 4, 2024
Vendor
Meta Platforms, Inc.
Product
HHVM
Classifications
CWE-125
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 3, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.32.1
  2. Affected versionversion=4.33.0 <unspecified
  3. Affected versionversion=4.38.1
  4. Affected versionversion=4.39.0
  5. Affected versionversion=4.39.1
  6. Affected versionversion=4.40.0
  7. Affected versionversion=4.40.1
  8. Affected versionversion=4.41.0
  9. Affected versionversion=4.41.1
  10. Affected versionversion=4.42.0
  11. Affected versionversion=4.42.1
  12. Affected versionversion=4.43.0
  13. Affected versionversion=4.43.1
  14. Affected versionversion=4.44.0
  15. Affected versionversion=4.44.1
  16. Affected versionversion=4.45.0
  17. Affected versionversion=4.45.1
  18. Affected versionversion=4.8.7
  19. Affected versionversion=4.9.0 <unspecified
  20. Affected versionversion=unspecified <=4.8.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Meta Platforms, Inc. · HHVMversion=4.32.1; version=4.33.0 <unspecified; version=4.38.1; version=4.39.0; version=4.39.1; version=4.40.0; version=4.40.1; version=4.41.0; version=4.41.1; version=4.42.0; version=4.42.1; version=4.43.0; version=4.43.1; version=4.44.0; version=4.44.1; version=4.45.0; version=4.45.1; version=4.8.7; version=4.9.0 <unspecified; version=unspecified <=4.8.6

Published CVSS scores

6.4NVDAV:N/AC:L/Au:N/C:P/I:N/A:P
8.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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