The malloc function in the GNU C Library (aka glibc or libc6) 2.26 could return a memory block that is too small if an attempt is made to allocate an object whose size is close to SIZE_MAX, potentially leading to a subsequent heap overflow. This occurs because the per-thread cache (aka tcache) feature enables a code path that lacks an integer overflow check.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2017-17426 from the MITRE CVE dictionary dictionary and NIST NVD.
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 |
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