Description
libxml2, possibly before 2.5.0, does not properly detect recursion during entity expansion, which allows context-dependent attackers to cause a denial of service (memory and CPU consumption) via a crafted XML document containing a large number of nested entity references, aka the "billion laughs 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.
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 2 | libxml2 +2 | 2.4.19-11.ent | RHSA-2008:0886 |
Advisories 1
- RHSA-2008:0886 Red Hat Security Advisory: libxml2 security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
References
- 31868 third-party-advisory
- http://xmlsoft.org/news.html
- [xml-dev] 20030202 Re: Elliotte Rusty Harold on Web Services mailing-list
- http://www.reddit.com/r/programming/comments/65843/time_to_upgrade_libxml2
- [xml] 20080820 Security fix for libxml2 mailing-list
- RHSA-2008:0886 vendor-advisory