CVE-2010-5109: Off-by-one error in the DecompressRTF function in ytnef.c in Yerase's TNEF Stream Reader allows remote atta...

Security readout for executives and security teams

CVE-2010-5109 is an old flaw in Yerase's TNEF Stream Reader handling of compressed RTF inside TNEF files. A specially crafted TNEF attachment could crash software that processes it. The public record describes denial of service, not confirmed code execution or active exploitation. Exposure is most likely where mail gateways, desktop clients, scanners, or backend services parse TNEF or winmail.dat content using the affected ytnef/libytnef code path. Organizations without TNEF parsing are unlikely to be exposed. Treat this as a targeted hygiene item, not an emergency, unless TNEF parsing is exposed in critical mail infrastructure. Prioritize patch verification and attachment filtering for mail gateways and automated parsers. Mitigation focus: Identify systems that process TNEF, winmail.dat, or compressed RTF mail attachments.; Check vendor or distribution advisories for patched ytnef/libytnef packages.; Update affected packages through trusted operating system or application channels..

Prepared

Jun 14, 2026, 14:32 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.