Junglewise Threat Intelligence

CVE-2016-9435: w3m uninitialized value use in HTMLtagproc1

CVE-2016-9435 · Severity: medium · CVSS 6.5 · Published 2017-01-20

Technologies: Opensuse Leap. Vendors: Opensuse.

Executive brief

w3m is a text-based web browser used to view websites in a terminal environment. A vulnerability in how it processes certain HTML tags allows a remote attacker to crash the browser by tricking a user into opening a specially crafted web page. This results in a denial-of-service, potentially disrupting the user's workflow or terminal session.

Technical details

A vulnerability exists in the w3m text-based browser due to the use of uninitialized values within the HTMLtagproc1 function in file.c. Specifically, when processing <dd> tags, the application may attempt to access environment variables or stack values that have not been properly set if the tag is not preceded by a proper <dl> (definition list) context. An attacker can exploit this by providing a maliciously crafted HTML file that triggers a conditional jump or move based on these uninitialized values, leading to an application crash (Denial of Service). The issue was identified using Valgrind and fixed by ensuring a proper environment is pushed when encountering <dd> tags. Patch availability is confirmed in the 0.5.3+git20161009 release.

Affected products

  • tats w3m before 0.5.3+git20161009

Timeline

  • 2016-08-17: disclosed: Issue reported on GitHub with Valgrind logs
  • 2016-10-09: patched: Fix committed to w3m repository
  • 2017-01-20: advisory: NVD advisory published

References

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