CVE-2019-3556Network attack vector

Authenticated file overwrite via unvalidated dump path

Published Oct 26, 2021 · Updated Aug 4, 2024

Path traversal in the HHVM admin server allows remote authenticated users to overwrite files writable by the HHVM process. The dump-pcre-cache handler passes its unvalidated file parameter directly to the PCRE cache dump routine, which opens that path for output. Access to the administrative HTTP interface is required, and successful requests can replace application, configuration, or service data within the process account's write permissions.

CVSS severity8.1
High
EPSS probability1.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in the HHVM admin server allows remote authenticated users to overwrite files writable by the HHVM process. The dump-pcre-cache handler passes its unvalidated file parameter directly to the PCRE cache dump routine, which opens that path for output. Access to the administrative HTTP interface is required, and successful requests can replace application, configuration, or service data within the process account's write permissions.

The record

CVE
CVE-2019-3556
Published
Oct 26, 2021
Updated
Aug 4, 2024
Vendor
Meta Platforms, Inc.
Product
HHVM
Classifications
CWE-22, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 26, 2021CVE 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=4.57.0 <unspecified
  2. Affected versionversion=4.79.0 <unspecified
  3. Affected versionversion=4.80.0 <unspecified
  4. Affected versionversion=4.81.0 <unspecified
  5. Affected versionversion=4.82.0 <unspecified
  6. Affected versionversion=4.83.0 <unspecified
  7. Affected versionversion=unspecified <4.56.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Meta Platforms, Inc. · HHVMversion=4.57.0 <unspecified; version=4.79.0 <unspecified; version=4.80.0 <unspecified; version=4.81.0 <unspecified; version=4.82.0 <unspecified; version=4.83.0 <unspecified; version=unspecified <4.56.2

Published CVSS scores

8.1NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
5.5NISTAV:N/AC:L/Au:S/C:N/I:P/A:P

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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