The VEGAOpBitmap::AddLine function in Opera before 10.61 does not properly initialize memory during processing of the SIZE attribute of a SELECT element, which allows remote attackers to trigger an invalid memory write operation, and consequently cause a denial of service (application crash) or possibly execute arbitrary code, via a large integer attribute value.
http://securityreason.com/securityalert/8244
https://exchange.xforce.ibmcloud.com/vulnerabilities/67338
http://www.kb.cert.org/vuls/id/778396
http://www.opera.com/docs/changelogs/mac/1061/