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Servers and applications

CVE-2017-9047

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)…

Severity
High 7.5
Published
18 May 2017
Last changed
14 Oct 2026
Added to UpHeron
1 Nov 2026
Exploit chance
3.2% in the next 30 daysHigher than 88% of CVEs. EPSS by FIRST, 11 Nov 2026
Weakness
Memory buffer errors (CWE-119)
Attack
Over the network · No login needed · No user action needed
Attacker can
Take it down
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Sources
NVD

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.

From NVD.

Affected software

SoftwareAffected versions
libxml2Servers and applications · cpe:a:xmlsoft:libxml2
  • Version 2.9.4

References

  • NVD https://nvd.nist.gov/vuln/detail/CVE-2017-9047
  • CVE.org https://www.cve.org/CVERecord?id=CVE-2017-9047