Buffer overflow in Facebook Hhvm
CVE-2020-1917
xbuf_format_converter, used as part of exif_read_data, was appending a terminating null character to the generated string, but was not using its standard append char function. As a result, if the buffer was full, it would result in an out-of-bounds write. 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
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.014 (71.7th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 71.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000
Affected products
- Facebook Hhvm — versions 4.98.1, 4.98.0, 4.97.1
Weakness classification (CWE)
References
- hhvm.com/blog/2021/02/25/security-update.html (Release Notes, Vendor Advisory)
- github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44ca (Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-1917?
- CVE-2020-1917 is a critical-severity vulnerability in Facebook Hhvm, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2021-03-10.
- How severe is CVE-2020-1917?
- Critical severity. CVSS v3 base score is 9.8 out of 10.