CVE-2020-1919 is a vulnerability in Facebook Hhvm
Published on March 10, 2021
Incorrect bounds calculations in substr_compare could lead to an out-of-bounds read when the second string argument passed in is longer than the first. 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.
Weakness Type
Out-of-bounds Read
The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.
Products Associated with CVE-2020-1919
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Affected Versions
Facebook HHVM:- Version 4.98.1 and below unspecified is unaffected.
- Version 4.98.0 is affected.
- Version 4.97.1 and below unspecified is unaffected.
- Version 4.97.0 is affected.
- Version 4.96.1 and below unspecified is unaffected.
- Version 4.96.0 is affected.
- Version 4.95.1 and below unspecified is unaffected.
- Version 4.95.0 is affected.
- Version 4.94.1 and below unspecified is unaffected.
- Version 4.94.0 is affected.
- Version 4.93.2 and below unspecified is unaffected.
- Version 4.81.0 and below unspecified is affected.
- Version 4.80.2 and below unspecified is unaffected.
- Version 4.57.0 and below unspecified is affected.
- Version 4.56.3 and below unspecified is unaffected.
- Version unspecified and below 4.56.3 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.