Heap-based Buffer Overflow Affecting libxml2 package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.29% (70th percentile)

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  • Snyk IDSNYK-CENTOS7-LIBXML2-1986245
  • published26 Jul 2021
  • disclosed15 May 2017

Introduced: 15 May 2017

CVE-2017-9047  (opens in a new tab)
CWE-122  (opens in a new tab)

How to fix?

There is no fixed version for Centos:7 libxml2.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libxml2 package and not the libxml2 package as distributed by Centos. See How to fix? for Centos:7 relevant fixed versions and status.

A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. The function xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a char buffer 'buf' of size 'size'. The variable len is assigned strlen(buf). If the content->type is XML_ELEMENT_CONTENT_ELEMENT, then (i) the content->prefix is appended to buf (if it actually fits) whereupon (ii) content->name is written to the buffer. However, the check for whether the content->name actually fits also uses 'len' rather than the updated buffer length strlen(buf). This allows us to write about "size" many bytes beyond the allocated memory. This vulnerability causes programs that use libxml2, such as PHP, to crash.