The malloc implementation in the GNU C Library (aka glibc or libc6), from version 2.24 to 2.26 on powerpc, and only in version 2.26 on i386, did not properly handle malloc calls with arguments close to SIZE_MAX and could return a pointer to a heap region that is smaller than requested, eventually leading to heap corruption.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2018-6551 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue did not affect the versions of glibc and compat-glibc as shipped with Red Hat Enterprise Linux 5, 6, and 7.
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
| CVSS3 Base Score | 5.3 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | Low |
| Integrity Impact | Low |
| Availability Impact | Low |
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 7 | glibc | Not affected |
| Red Hat Enterprise Linux 7 | compat-glibc | Not affected |
| Red Hat Enterprise Linux 6 | glibc | Not affected |
| Red Hat Enterprise Linux 6 | compat-glibc | Not affected |
| Red Hat Enterprise Linux 5 | compat-glibc | Not affected |
| Red Hat Enterprise Linux 5 | glibc | Not affected |
Vulmon