CVE-2018-6307 - Use After Free

Severity

68%

Complexity

86%

Confidentiality

106%

LibVNC before commit ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.

LibVNC before commit ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.

CVSS 3.0 Base Score 8.1. CVSS Attack Vector: network. CVSS Attack Complexity: high. CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 6.8. CVSS Attack Vector: network. CVSS Attack Complexity: medium. CVSS Vector: (AV:N/AC:M/Au:N/C:P/I:P/A:P).

Demo Examples

Use After Free

CWE-416

The following example demonstrates the weakness.


               
}
free(buf3R2);

Use After Free

CWE-416

The following code illustrates a use after free error:


               
}
free(ptr);
logError("operation aborted before commit", ptr);

When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function.

Overview

First reported 6 years ago

2018-12-19 16:29:00

Last updated 5 years ago

2019-10-31 01:15:00

Affected Software

Canonical Ubuntu Linux 14.04 LTS (Long-Term Support)

14.04

Canonical Ubuntu Linux 16.04 LTS (Long-Term Support)

16.04

Canonical Ubuntu Linux 18.04 LTS Edition

18.04

Canonical Ubuntu Linux 18.10

18.10

Debian Linux 8.0 (Jessie)

8.0

Debian Linux 9.0

9.0

References

https://github.com/LibVNC/libvncserver/issues/241

Third Party Advisory

https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-026-libvnc-heap-use-after-free/

Third Party Advisory

[debian-lts-announce] 20181227 [SECURITY] [DLA 1617-1] libvncserver security update

Mailing List, Third Party Advisory

[debian-lts-announce] 20191030 [SECURITY] [DLA 1979-1] italc security update

USN-3877-1

Third Party Advisory

DSA-4383

Third Party Advisory

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