{"id":"DEBIAN-CVE-2026-64620","details":"FreeRDP before 3.28.0 (affected \u003c=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The function writes the modular-exponentiation result into the caller's output buffer via BN_bn2bin() and only afterward checks output_length \u003e out_length, so out-of-bounds bytes are written before the bounds check. On the server side, when a client selects RDP Standard Security, the encrypted client random is decrypted into a fixed 32-byte buffer. Because the server publishes its RSA public key, an unauthenticated attacker can forge a ciphertext whose decrypted value is up to the full modulus length (e.g. 256 bytes for RSA-2048), overflowing the 32-byte heap buffer by up to ~224 attacker-controlled bytes pre-authentication, resulting in denial of service.","modified":"2026-09-01T16:06:56.446207643Z","published":"2026-07-20T12:19:46.760Z","upstream":["CVE-2026-64620"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-64620"}],"affected":[{"package":{"name":"freerdp2","ecosystem":"Debian:12","purl":"pkg:deb/debian/freerdp2?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.0+dfsg1-1","2.10.0+dfsg1-1.1","2.11.2+dfsg1-1","2.11.2+dfsg1-1.1~exp1","2.11.2+dfsg1-1.1~exp2","2.11.5+dfsg1-1","2.11.7+dfsg1-1","2.11.7+dfsg1-2","2.11.7+dfsg1-3","2.11.7+dfsg1-4","2.11.7+dfsg1-5","2.11.7+dfsg1-6","2.11.7+dfsg1-6~deb12u1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64620.json"}},{"package":{"name":"freerdp3","ecosystem":"Debian:13","purl":"pkg:deb/debian/freerdp3?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.15.0+dfsg-2.1","3.15.0+dfsg-2.1+deb13u1","3.15.0+dfsg-2.1+deb13u2","3.15.0+dfsg-2.1+deb13u3","3.16.0+dfsg-1","3.16.0+dfsg-2","3.17.0+dfsg-1","3.17.1+dfsg-1","3.17.1+dfsg-2","3.17.2+dfsg-1","3.17.2+dfsg-2","3.17.2+dfsg-3","3.18.0+dfsg-1","3.19.0+dfsg-1","3.19.1+dfsg-1","3.20.0+dfsg-1","3.20.2+dfsg-1","3.21.0+dfsg-1","3.22.0+dfsg-1","3.22.0+dfsg-1~bpo13+0","3.22.0+dfsg-1~bpo13+1","3.22.0+dfsg-3","3.23.0+dfsg-1","3.23.0+dfsg-1~bpo13+1","3.24.0+dfsg-1","3.24.0+dfsg-2","3.24.1+dfsg-1","3.24.2+dfsg-1","3.24.2+dfsg-1~bpo13+1","3.25.0+dfsg-1","3.25.0+dfsg-2","3.25.0+dfsg-3","3.25.0+dfsg-4","3.25.0+dfsg-5","3.26.0+dfsg-1","3.26.0+dfsg-1~bpo13+1","3.27.0+dfsg-1","3.27.1+dfsg-1","3.28.0+dfsg-1","3.28.0+dfsg-2","3.29.0+dfsg-1","3.30.0+dfsg-1","3.30.0+dfsg-1~bpo13+1","3.31.0+dfsg-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64620.json"}},{"package":{"name":"freerdp3","ecosystem":"Debian:14","purl":"pkg:deb/debian/freerdp3?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.28.0+dfsg-1"}]}],"versions":["3.15.0+dfsg-2.1","3.16.0+dfsg-1","3.16.0+dfsg-2","3.17.0+dfsg-1","3.17.1+dfsg-1","3.17.1+dfsg-2","3.17.2+dfsg-1","3.17.2+dfsg-2","3.17.2+dfsg-3","3.18.0+dfsg-1","3.19.0+dfsg-1","3.19.1+dfsg-1","3.20.0+dfsg-1","3.20.2+dfsg-1","3.21.0+dfsg-1","3.22.0+dfsg-1","3.22.0+dfsg-1~bpo13+0","3.22.0+dfsg-1~bpo13+1","3.22.0+dfsg-3","3.23.0+dfsg-1","3.23.0+dfsg-1~bpo13+1","3.24.0+dfsg-1","3.24.0+dfsg-2","3.24.1+dfsg-1","3.24.2+dfsg-1","3.24.2+dfsg-1~bpo13+1","3.25.0+dfsg-1","3.25.0+dfsg-2","3.25.0+dfsg-3","3.25.0+dfsg-4","3.25.0+dfsg-5","3.26.0+dfsg-1","3.26.0+dfsg-1~bpo13+1","3.27.0+dfsg-1","3.27.1+dfsg-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-64620.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H"}]}