CVE-2017-9047

MEDIUM

Description

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.

References

http://www.debian.org/security/2017/dsa-3952

http://www.openwall.com/lists/oss-security/2017/05/15/1

http://www.securityfocus.com/bid/98599

https://security.gentoo.org/glsa/201711-01

Details

Source: MITRE

Published: 2017-05-18

Updated: 2017-11-11

Type: CWE-119

Risk Information

CVSS v2.0

Base Score: 5

Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P

Impact Score: 2.9

Exploitability Score: 10

Severity: MEDIUM

CVSS v3.0

Base Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Impact Score: 3.6

Exploitability Score: 3.9

Severity: HIGH