CVE-2026-64620 Detail
Received
This CVE record has recently been published to the CVE List and has been included within the NVD dataset. DescriptionFreeRDP before 3.28.0 (affected <=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 > 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. Metrics
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CVSS 4.0 Severity and Vector Strings:
CNA: VulnCheck
CVSS-B 9.3 CRITICAL
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
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Quick InfoCVE Dictionary Entry:CVE-2026-64620 NVD Published Date: 07/20/2026 NVD Last Modified: 07/20/2026 Source: VulnCheck |
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