CVE-2018-10887: debian debian_linux Unexpected Sign Extension

Vulnerability summary

CVE-2018-10887 is a high (CVSS 8.1) Unexpected Sign Extension vulnerability in debian debian_linux. EPSS estimates a 2.05% chance of exploitation in the next 30 days, higher than 80.9% of scored vulnerabilities.

Timeline

1. 10-07-2018
   PublishedVulnerability first disclosed.
2. 17-09-2024
   Last modifiedVulnerability information updated.

Description

A flaw was found in libgit2 before version 0.27.3. It has been discovered that an unexpected sign extension in git_delta_apply function in delta.c file may lead to an integer overflow which in turn leads to an out of bound read, allowing to read before the base object. An attacker may use this flaw to leak memory addresses or cause a Denial of Service.

• CWE-194Unexpected Sign ExtensionThe product performs an operation on a number that causes it to be sign extended when it is transformed into a larger data type. When the original number is negative, this can produce unexpected values that lead to resultant weaknesses.
• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.
• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
• CWE-681Incorrect Conversion between Numeric TypesWhen converting from one data type to another, such as long to integer, data can be omitted or translated in a way that produces unexpected values. If the resulting values are used in a sensitive context, then dangerous behaviors may occur.