libcurl 7.49.0 to and including 7.57.0 contains an out bounds read in code handling HTTP/2 trailers. It was reported (https://github.com/curl/curl/pull/2231) that reading an HTTP/2 trailer could mess up future trailers since the stored size was one byte less than required. The problem is that the code that creates HTTP/1-like headers from the HTTP/2 trailer data once appended a string like `:` to the target buffer, while this was recently changed to `: ` (a space was added after the colon) but the following math wasn't updated correspondingly. When accessed, the data is read out of bounds and causes either a crash or that the (too large) data gets passed to client write. This could lead to a denial-of-service situation or an information disclosure if someone has a service that echoes back or uses the trailers for something.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2018-1000005 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 | 4.8 |
|---|---|
| CVSS3 Base Metrics | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L |
| Attack Vector | Network |
| Attack Complexity | High |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | Low |
| Integrity Impact | None |
| Availability Impact | Low |
| Platform | Package | State |
|---|---|---|
| Red Hat Software Collections for Red Hat Enterprise Linux | httpd24-curl | Not affected |
| Red Hat JBoss Core Services 1 | curl | Affected |
| Red Hat Enterprise Linux 7 | curl | Not affected |
| Red Hat Enterprise Linux 6 | curl | Not affected |
| Red Hat Enterprise Linux 5 | curl | Not affected |
| Red Hat Ceph Storage 2 | curl | Not affected |
| .NET Core 2.0 on Red Hat Enterprise Linux | rh-dotnet20-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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