Description
OpenSSL 0.9.6 and 0.9.7 does not properly track the number of characters in certain ASN.1 inputs, which allows remote attackers to cause a denial of service (crash) via an SSL client certificate that causes OpenSSL to read past the end of a buffer when the long form is used.
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 ↗Advisories 2
- DSA-393 openssl - denial of service Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-394 openssl095 - ASN.1 parsing vulnerability Debian Security (DSA / DLA) · Mar 9, 2026
References
- RHSA-2003:292 vendor-advisory
- oval:org.mitre.oval:def:4574 vdb-entry signature
- VU#380864 third-party-advisory
- openssl-asn1-sslclient-dos(43041) vdb-entry
- ADV-2006-3900 vdb-entry
- DSA-393 vendor-advisory
- http://www-1.ibm.com/support/docview.wss?uid=swg21247112
- http://www.uniras.gov.uk/vuls/2003/006489/openssl.htm
- DSA-394 vendor-advisory
- RHSA-2003:291 vendor-advisory
- CA-2003-26 third-party-advisory
- 22249 third-party-advisory
- 8732 vdb-entry
- 201029 vendor-advisory
- http://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=104893
- ESA-20030930-027 vendor-advisory