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.
Se detectó un desbordamiento de búfer en libxml2 versión 20904-GITv2.9.4-16-g0741801. La función xmlSnprintfElementContent en el archivo valid.c debe volcar recursivamente la definición del contenido del elemento en un búfer de caracteres 'buf' de tamaño "size". La variable len es asignada strlen (buf). Si el content-)type es XML_ELEMENT_CONTENT_ELEMENT, entonces (i) content-)prefix se agrega a buf (si realmente encaja) con lo cual (ii) content-)name se escribe en el búfer. Sin embargo, la comprobación de si el content-)name realmente se ajusta también usa 'len' en lugar de la longitud de búfer actualizada (buf). Esto nos permite escribir sobre "size" muchos bytes más allá de la memoria asignada. Esta vulnerabilidad causa que los programas que usan libxml2, como PHP, se bloqueen.
AV:N/AC:L/Au:N/C:N/I:N/A:P
| Access Vector | NETWORK |
|---|---|
| Access Complexity | LOW |
| Authentication | NONE |
| Confidentiality Impact | NONE |
| Integrity Impact | NONE |
| Availability Impact | PARTIAL |
| Source | Type | Description |
|---|---|---|
| [email protected] | Primary |
en
CWE-119
|
| Vendor | Product | Version | Update | Type |
|---|---|---|---|---|
| xmlsoft | libxml2 | 2.9.4 | <built-in method update of dict object at 0x7fd34b8d9e00> | Application |
| Vulnerable | CPE |
|---|---|
| Yes | cpe:2.3:a:xmlsoft:libxml2:2.9.4:*:*:*:*:*:*:* |