CVE-2019-14842 in Libguestfs and Red Hat Products
Published on November 26, 2019
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.
Weakness Type
Incorrect Conversion between Numeric Types
When converting from one data type to another, such as long to integer, data can be omitted or translated in a way that produces unexpected values. If the resulting values are used in a sensitive context, then dangerous behaviors may occur.
Products Associated with CVE-2019-14842
stack.watch emails you whenever new vulnerabilities are published in Libguestfs Libnbd or Red Hat Libnbd. Just hit a watch button to start following.
Affected Versions
[UNKNOWN] libnbd Version 1.0.3 is affected by CVE-2019-14842Exploit Probability
EPSS
0.22%
Percentile
43.91%
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.