CVE-2026-48840 PROXYv2 parser: reject PROXY frames whose declared payload length is too short for the claimed address family (12 bytes for
On Sat, May 30, 2026 at 3:39 PM Andreas Metzler <[email protected]> wrote: > Andreas Metzler uploaded new packages for exim4 which fixed the > following security problems: > > CVE-2026-48840 > PROXYv2 parser: reject PROXY frames whose declared payload > length is too short for the claimed address family (12 bytes for > TCPv4/0x11, 36 bytes for TCPv6/0x21). Previously a frame with > family=0x21 and len=0 caused 16 bytes of uninitialized stack to be > formatted as the sender's IPv6 address and disclosed in the SMTP > greeting banner. Affects configurations with SUPPORT_PROXY and > `hosts_proxy` set. Reported by Warisjeet Singh (sin99xx). > EXIM-Security-2026-05-19.1 > > For the trixie-backports distribution the problem has been fixed in > version 4.99.3-2~bpo13+1. >
