CVE-2020-1900
No exploitation reported by the sources we read.
- Published2021-03-11
- Fixed in4.56.1 · 4.32.3
- WeaknessCWE-416
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
When unserializing an object with dynamic properties HHVM needs to pre-reserve the full size of the dynamic property array before inserting anything into it. Otherwise the array might resize, invalidating previously stored references. This pre-reservation was not occurring in 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.
Timeline
dates in UTC- 2021-03-1101:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 18:48 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-1900?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-1900?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 4.x | ≥ 4.33.0, < 4.56.1 | 4.56.1 | NVD |
| 4.32 | < 4.32.3 | 4.32.3 | NVD |
| 4.57 | = 4.57.0 | no fix published | NVD |
| 4.58 | = 4.58.0 | no fix published | NVD |
| 4.58 | = 4.58.1 | no fix published | NVD |
| 4.59 | = 4.59.0 | no fix published | NVD |
| 4.60 | = 4.60.0 | no fix published | NVD |
| 4.61 | = 4.61.0 | no fix published | NVD |
| 4.62 | = 4.62.0 | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Facebook hhvm to 4.56.1 · 4.32.3
Advisories and patches
- github.comPatch
- hhvm.comVendor Advisory
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
- NVDCVSS 3.19.8read 2026-10-23
- NVDCVSS 2.07.5read 2026-10-23
- CNAweakness (CWE)CWE-416read 2026-10-23
- NVDweakness (CWE)CWE-416read 2026-10-23
- FIRST EPSSEPSS score1.4 %2026-10-22
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Published
- 2021-03-11
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2020-1900?
Is CVE-2020-1900 actively exploited?
What is the CVSS score for CVE-2020-1900?
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