CVE-2019-14842

published 2019-11-26

CVE-2019-14842: Structured reply is a feature of the newstyle NBD protocol allowing the server to send a reply in chunks. A bounds check which was supposed to test for chunk…

Priority P3 55 critical 9.8 CVSS 3.1

AV N AC L PR N UI N S U C H I H A H

Structured reply is a feature of the newstyle NBD protocol allowing the server to send a reply in chunks. A bounds check which was supposed to test for chunk offsets smaller than the beginning of the request did not work because of signed/unsigned confusion. If one of these chunks contains a negative offset then data under control of the server is written to memory before the read buffer supplied by the client. If the read buffer is located on the stack then this allows the stack return address from nbd_pread() to be trivially modified, allowing arbitrary code execution under the control of the server. If the buffer is located on the heap then other memory objects before the buffer can be overwritten, which again would usually lead to arbitrary code execution.

Affected

6 ranges

Vendor	Product	Version range	Fixed in
debian	libnbd	< libnbd 1.0.3-1 (bookworm)	libnbd 1.0.3-1 (bookworm)
redhat	libnbd	< 1.0.3	1.0.3
redhat	libnbd	>= 0 < 1.0.3-1	1.0.3-1
redhat	libnbd	>= 0 < 1.0.3-1	1.0.3-1
redhat	libnbd	>= 0 < 1.0.3-1	1.0.3-1
redhat	libnbd	>= 0 < 1.0.3-1	1.0.3-1

CVSS provenance

nvd v3.1 9.8 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd v3.0 7.3 HIGH CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

nvd v2.0 7.5 HIGH AV:N/AC:L/Au:N/C:P/I:P/A:P

osv 9.8 CRITICAL

vendor_debian 9.8 CRITICAL

vendor_redhat 9.8 CRITICAL

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CWE-681