HOMEVULNERABILITIESCVE-2020-1899
HIGH

CVE-2020-1899

CWE-822Published: March 11, 2021· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official Description

The unserialize() function supported a type code, "S", which was meant to be supported only for APC serialization. This type code allowed arbitrary memory addresses to be accessed as if they were static StringData objects. This issue affected HHVM prior to v4.32.3, between versions 4.33.0 and 4.56.0, 4.57.0, 4.58.0, 4.58.1, 4.59.0, 4.60.0, 4.61.0, 4.62.0.

NVD Source

Technical Analysis

CVE-2020-1899 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected Vendors & Products

facebook1 product(s)
hhvm
Source: NVD CPE · 8 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://github.com/facebook/hhvm/commit/1107228a5128d3ca1c4add8ac1635d933cbbe2e9
PATCHhttps://github.com/facebook/hhvm/commit/1107228a5128d3ca1c4add8ac1635d933cbbe2e9
ADVISORYhttps://hhvm.com/blog/2020/06/30/security-update.html
ADVISORYhttps://hhvm.com/blog/2020/06/30/security-update.html

All References (4)

→
https://github.com/facebook/hhvm/commit/1107228a5128d3ca1c4add8ac1635d933cbbe2e9Patch · Third Party Advisory
→
https://hhvm.com/blog/2020/06/30/security-update.htmlVendor Advisory
→
https://github.com/facebook/hhvm/commit/1107228a5128d3ca1c4add8ac1635d933cbbe2e9Patch · Third Party Advisory
→
https://hhvm.com/blog/2020/06/30/security-update.htmlVendor Advisory

Quick Facts

CVE IDCVE-2020-1899
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-822
CISA KEVNo
Affected1 vendor(s)
PublishedMar 11, 2021

Related CVEs (CWE-822)

CVE-2025-50165
9.8
CVE-2026-48137
9.8
CVE-2018-17893
9.8
CVE-2023-1437
9.8
CVE-2018-14811
9.8
CVE-2023-43518
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2020-1899 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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