CVE-2019-19624
Description
An out-of-bounds read vulnerability was discovered in OpenCV. This flaw can be exploited when a small, carefully crafted image is loaded by an application linked to OpenCV. A remote attacker could exploit this flaw, causing a denial of service by causing the application to crash or read sensitive information from memory.
Statement
This issue did not affect the versions of OpenCV as shipped with Red Hat Enterprise Linux 6, and 7 as they did not include support for DIS optflow algorithm. This issue affects OpenCV as shipped with Red Hat Enterprise Linux 8. However, the package has been built with C++ standard library hardening (_GLIBCXX_ASSERTIONS) that enables range checks for C++ arrays, vectors, and strings. This leads to an application exit due to an assertion statement and prevents the out-of-bounds read to be exploitable.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | 6.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | Low | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | Low | N/A |
Vector
Red Hat: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Red Hat CVSS v3 Score Explanation
The key difference between our CVSS score and NVD's involves the Confidentiality metric. We consider the Confidentiality to be None (C:N versus C:L) because OpenCV has been built with C++ standard library hardening. This causes the application to always exit in a controlled way, with no impact to the confidentiality of the affected component.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely 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.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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