Description
Memory leak in the zlib_stateful_init function in crypto/comp/c_zlib.c in libssl in OpenSSL 0.9.8f through 0.9.8h allows remote attackers to cause a denial of service (memory consumption) via multiple calls, as demonstrated by initial SSL client handshakes to the Apache HTTP Server mod_ssl that specify a compression algorithm.
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 | apache2 | 2.2.8-4 | — |
| Debian 13 | apache2 | 2.2.8-4 | — |
| Debian 12 | apache2 | 2.2.8-4 | — |
| Debian 5.0 | apache2 | 2.2.8-4~lenny1 | DTSA-131-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | httpd +2 | 2.2.3-22.el5_3.1 | RHSA-2009:1075 |
| RHEL 5 | mod_ssl | 1:2.2.3-22.el5_3.1 | RHSA-2009:1075 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | apache2 | 2.4.49-1.1 | openSUSE-SU-2024:10623-1 |
Advisories 3
- RHSA-2009:1075 Red Hat Security Advisory: httpd security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DTSA-131-1 apache2 - denial of service (memory leak in mod_ssl) Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10623-1 apache2-2.4.49-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- RHSA-2009:1075 vendor-advisory
- 42724 third-party-advisory
- 34219 third-party-advisory
- openssl-libssl-dos(43948) vdb-entry
- https://bugzilla.redhat.com/show_bug.cgi?id=447268
- 31026 third-party-advisory
- SSA:2010-060-02 vendor-advisory
- 31692 vdb-entry
- SUSE-SR:2008:024 vendor-advisory
- oval:org.mitre.oval:def:9754 vdb-entry signature
- 31681 vdb-entry
- https://issues.apache.org/bugzilla/show_bug.cgi?id=44975
- 38761 third-party-advisory
- 31416 third-party-advisory
- 44183 third-party-advisory
- USN-731-1 vendor-advisory
- http://bugs.gentoo.org/show_bug.cgi?id=222643
- 32222 third-party-advisory
- 35264 third-party-advisory
- MDVSA-2009:124 vendor-advisory
- http://svn.apache.org/viewvc?view=rev&revision=654119
- FEDORA-2008-6393 vendor-advisory
- GLSA-200807-06 vendor-advisory
- https://bugs.edge.launchpad.net/bugs/224945
- ADV-2008-2780 vdb-entry
- https://bugs.edge.launchpad.net/bugs/186339
- https://kb.bluecoat.com/index?page=content&id=SA50
- 3981 third-party-advisory
- [openssl-dev] 20080512 possible memory leak in zlib compression mailing-list
- APPLE-SA-2008-10-09 vendor-advisory
- http://support.apple.com/kb/HT3216
- 42733 third-party-advisory