Off-by-one error in the inflate function in Zlib.xs in Compress::Raw::Zlib Perl module before 2.017, as used in AMaViS, SpamAssassin, and possibly other products, allows context-dependent attackers to cause a denial of service (hang or crash) via a crafted zlib compressed stream that triggers a heap-based buffer overflow, as exploited in the wild by Trojan.Downloader-71014 in June 2009.

• http://article.gmane.org/gmane.mail.virus.amavis.user/33635
• http://article.gmane.org/gmane.mail.virus.amavis.user/33638
• http://www.securityfocus.com/bid/35307
• http://secunia.com/advisories/35422
• https://bugzilla.redhat.com/show_bug.cgi?id=504386
• http://www.vupen.com/english/advisories/2009/1571
• http://thread.gmane.org/gmane.mail.virus.amavis.user/33635
• http://osvdb.org/55041
• http://lists.opensuse.org/opensuse-security-announce/2009-07/msg00002.html
• http://secunia.com/advisories/35876
• http://secunia.com/advisories/35685
• https://www.redhat.com/archives/fedora-package-announce/2009-July/msg00607.html
• http://secunia.com/advisories/35689
• http://www.mandriva.com/security/advisories?name=MDVSA-2009:157
• http://security.gentoo.org/glsa/glsa-200908-07.xml
• https://bugs.gentoo.org/show_bug.cgi?id=273141
• https://exchange.xforce.ibmcloud.com/vulnerabilities/51062
• https://usn.ubuntu.com/794-1/

Compress::Raw::Zlib versions through 2.219 for Perl use potentially insecure versions of zlib. Compress::Raw::Zlib includes a copy of the zlib library. Compress::Raw::Zlib version 2.220 includes zlib 1.3.2, which addresses findings fron the 7ASecurity audit of zlib. The includes fixs for CVE-2026-27171.

• https://7asecurity.com/blog/2026/02/zlib-7asecurity-audit/
• https://github.com/madler/zlib
• https://github.com/madler/zlib/releases/tag/v1.3.2
• https://metacpan.org/release/PMQS/Compress-Raw-Zlib-2.221/source/Changes
• https://www.cve.org/CVERecord?id=CVE-2026-27171
• https://www.zlib.net/