CVE-2021-3939 vulnerability in Canonical Products
Published on November 17, 2021
Free of static data in accountsservice
Ubuntu-specific modifications to accountsservice (in patch file debian/patches/0010-set-language.patch) caused the fallback_locale variable, pointing to static storage, to be freed, in the user_change_language_authorized_cb function. This is reachable via the SetLanguage dbus function. This is fixed in versions 0.6.55-0ubuntu12~20.04.5, 0.6.55-0ubuntu13.3, 0.6.55-0ubuntu14.1.
Vulnerability Analysis
CVE-2021-3939 can be exploited with local system access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
Free of Memory not on the Heap
The application calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc(). When free() is called on an invalid pointer, the program's memory management data structures may become corrupted. This corruption can cause the program to crash or, in some circumstances, an attacker may be able to cause free() to operate on controllable memory locations to modify critical program variables or execute code.
Products Associated with CVE-2021-3939
stack.watch emails you whenever new vulnerabilities are published in Canonical Accountsservice or Canonical Ubuntu Linux. Just hit a watch button to start following.
Affected Versions
Ubuntu accountsservice:- Version 0.6.55-0ubuntu12~20.04 and below 0.6.55-0ubuntu12~20.04.5 is affected.
- Version 0.6.55-0ubuntu13 and below 0.6.55-0ubuntu13.3 is affected.
- Version 0.6.55-0ubuntu14 and below 0.6.55-0ubuntu14.1 is affected.
Exploit Probability
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.