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

Source: https://junglewise.ai/threats/cve-2016-9435-w3m-uninitialized-value-use-in-htmltagproc1  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2017-01-20. Updated: 2026-05-13  
License: CC BY 4.0 with a link back

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

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.

Technologies: [Opensuse Leap](https://junglewise.ai/threats/technologies/leap). Vendors: [Opensuse](https://junglewise.ai/threats/vendors/opensuse).

## Quick answers

**Is CVE-2016-9435 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2016-9435 being exploited in the wild.

**How severe is CVE-2016-9435?** Medium severity, with a CVSS score of 6.5, published 20 January 2017.

**Which products and versions are affected?** tats w3m before 0.5.3+git20161009.

**Is there a fix for CVE-2016-9435?** A patch was published on 2016-10-09: Fix committed to w3m repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2016-9435 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2016-9435?** Check whether you run Opensuse Leap or Tats W3m. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## 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

- [http://lists.opensuse.org/opensuse-updates/2016-12/msg00084.html](http://lists.opensuse.org/opensuse-updates/2016-12/msg00084.html)
- [http://www.openwall.com/lists/oss-security/2016/11/18/3](http://www.openwall.com/lists/oss-security/2016/11/18/3)
- [http://www.securityfocus.com/bid/94407](http://www.securityfocus.com/bid/94407)
- [https://github.com/tats/w3m/commit/33509cc81ec5f2ba44eb6fd98bd5c1b5873e46bd](https://github.com/tats/w3m/commit/33509cc81ec5f2ba44eb6fd98bd5c1b5873e46bd)
- [https://github.com/tats/w3m/issues/16](https://github.com/tats/w3m/issues/16)
- [https://security.gentoo.org/glsa/201701-08](https://security.gentoo.org/glsa/201701-08)

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