Description
plugins/mod_compression.lua in (1) Prosody before 0.9.4 and (2) Lightwitch Metronome through 3.4 negotiates stream compression while a session is unauthenticated, which allows remote attackers to cause a denial of service (resource consumption) via compressed XML elements in an XMPP stream, aka an "xmppbomb" attack.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | lua-expat | 1.3.0-1 | — |
| Debian 14 | prosody | 0.9.4-1 | — |
| Debian 13 | lua-expat | 1.3.0-1 | — |
| Debian 13 | prosody | 0.9.4-1 | — |
| Debian 12 | lua-expat | 1.3.0-1 | — |
| Debian 12 | prosody | 0.9.4-1 | — |
| Debian 7 | prosody | 0.8.2-4+deb7u1 | DSA-2895-1 |
Advisories 1
- DSA-2895-1 prosody - security update Debian Security (DSA / DLA) · Mar 9, 2026
References
- http://xmpp.org/resources/security-notices/uncontrolled-resource-consumption-with-highly-compressed-xmpp-stanzas/
- DSA-2895 vendor-advisory
- 57710 third-party-advisory
- http://code.lightwitch.org/metronome/rev/49f47277a411
- http://blog.prosody.im/prosody-0-9-4-released/
- http://hg.prosody.im/0.9/rev/b3b1c9da38fb
- [oss-security] 20140408 Re: (Openfire M-Link Metronome Prosody Tigase) Possible CVE Request: Uncontrolled Resource Consumption with XMPP-Layer Compression mailing-list
- [oss-security] 20140407 Re: Possible CVE Request: Uncontrolled Resource Consumption with XMPP-Layer Compression mailing-list