A heap use-after-free flaw was found in curl versions from 7.59.0 through 7.61.1 in the code related to closing an easy handle. When closing and cleaning up an 'easy' handle in the `Curl_close()` function, the library code first frees a struct (without nulling the pointer) and might then subsequently erroneously write to a struct field within that already freed struct.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2018-16840 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 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L |
| Attack Vector | Network |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | Required |
| Scope | Unchanged |
| Confidentiality | Low |
| Integrity Impact | Low |
| Availability Impact | Low |
| Platform | Package | State |
|---|---|---|
| Red Hat Software Collections for Red Hat Enterprise Linux | httpd24-curl | Affected |
| Red Hat JBoss Web Server 5 | curl | Under investigation |
| Red Hat JBoss Core Services 1 | curl | Under investigation |
| Red Hat Enterprise Linux 7 | curl | Not affected |
| Red Hat Enterprise Linux 6 | curl | Not affected |
| Red Hat Enterprise Linux 5 | curl | Not affected |
| .NET Core 2.0 on Red Hat Enterprise Linux | rh-dotnet21-curl | Not affected |
| .NET Core 1.0 on Red Hat Enterprise Linux | rh-dotnetcore10-curl | Not affected |
| .NET Core 1.0 on Red Hat Enterprise Linux | rh-dotnetcore11-curl | Not affected |
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