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CVE-2020-1900

31
FAUCET Score

CVE-2020-1900 is a critical deserialization vulnerability affecting HHVM versions prior to 4.32.3, and specific ranges between 4.33.0 and 4.62.0. The flaw stems from HHVM's failure to properly pre-reserve memory for dynamic properties during object unserialization, potentially leading to memory corruption. With a CVSS score of 9.8 (CRITICAL), this vulnerability is easily exploitable over the network with low attack complexity, allowing for complete compromise of confidentiality, integrity, and availability. While there is no evidence of active exploitation or public exploit code, the vulnerability has garnered significant community discussion, indicating awareness among security researchers.

Impacted Technologies

VendorProductVersion(s)CPE
< 4.32.3CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*
>= 4.33.0, < 4.56.1CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:*:*:*:*:*:*:*:*
4.57.0CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:4.57.0:*:*:*:*:*:*:*
4.58.0CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:4.58.0:*:*:*:*:*:*:*
4.58.1CPE matchmatch criteria
cpe:2.3:a:facebook:hhvm:4.58.1:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.38%
Probability of exploitation in next 30 days
EPSS Percentile
69.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0138 is in the 56th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / facebook/hhvm/commit/c1c4bb0cf9e076aafaf4ff3515556ef9faf906f3
PatchThird Party Advisory
hhvm.com / blog/2020/06/30/security-update.html
Vendor Advisory