Buffer overflow in Facebook Hhvm
CVE-2020-1921
In the crypt function, we attempt to null terminate a buffer using the size of the input salt without validating that the offset is within the buffer. This issue affects HHVM versions prior to 4.56.3, all versions between 4.57.0 and 4.80.1, all versions between 4.81.0 and 4.93.1, and versions 4.94.0, 4.95.0, 4.96.0, 4.97.0, 4.98.0.
Vulnerability class: Buffer Overflow
EPSS: 0.012 (65.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Facebook Hhvm — versions 4.98.1, 4.98.0, 4.97.1
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve-assign@fb.com (x_refsource_MISC, Vendor Advisory)
- cve-assign@fb.com (Patch, Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2020-1921?
- CVE-2020-1921 is a high-severity vulnerability in Facebook Hhvm, classified under Stack-based Buffer Overflow. CVSS score: 7.5/10. Published 2021-03-10.
- How severe is CVE-2020-1921?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2020-1921 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.