In the PatternMatch function in fontfile/fontdir.c in libXfont through 1.5.2 and 2.x before 2.0.2, an attacker with access to an X connection can cause a buffer over-read during pattern matching of fonts, leading to information disclosure or a crash (denial of service). This occurs because '\0' characters are incorrectly skipped in situations involving ? characters.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2017-13720 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 | 4.4 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L |
| Attack Vector | Local |
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | Low |
| Integrity Impact | None |
| Availability Impact | Low |
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 7 | libXfont | Will not fix |
| Red Hat Enterprise Linux 7 | libXfont2 | Will not fix |
| Red Hat Enterprise Linux 6 | libXfont | Will not fix |
| Red Hat Enterprise Linux 5 | libXfont | Will not fix |
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