CVE-2022-2309

Description

NULL Pointer Dereference allows attackers to cause a denial of service (or application crash). This only applies when lxml is used together with libxml2 2.9.10 through 2.9.14. libxml2 2.9.9 and earlier are not affected. It allows triggering crashes through forged input data, given a vulnerable code sequence in the application. The vulnerability is caused by the iterwalk function (also used by the canonicalize function). Such code shouldn't be in wide-spread use, given that parsing + iterwalk would usually be replaced with the more efficient iterparse function. However, an XML converter that serialises to C14N would also be vulnerable, for example, and there are legitimate use cases for this code sequence. If untrusted input is received (also remotely) and processed via iterwalk function, a crash can be triggered.

How to fix CVE-2022-2309

To remediate CVE-2022-2309, upgrade the affected package to a fixed version below.

• —upgrade to 2.9.14-r1 or later
• —upgrade to 4.9.2-r0 or later
• —upgrade to 2.9.10+dfsg-6.7+deb11u5 or later
• —no fix listed
• —upgrade to 4.9.1 or later
• —upgrade to 86368e9cf70a0ad23cccd5ee32de847149af0c6f or later

Is CVE-2022-2309 being exploited?

Low — EPSS is 1.3%, meaning exploitation activity has not been observed at scale.

Affected packages (6)

• from 0, < 2.9.14-r1
• from 0, < 4.9.2-r0
• from 0, < 2.9.10+dfsg-6.7+deb11u5
• from 0
• from 0, < 4.9.1
• from 0, < 86368e9cf70a0ad23cccd5ee32de847149af0c6f | from 0, < 4.9.1

CVSS scores

References (16)

• ADVISORYgithub.com/advisories/GHSA-wrxv-2j5q-m38w
• ADVISORYnvd.nist.gov/vuln/detail/CVE-2022-2309
• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2022-2309
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2022-2309
• PATCH