CVE WatchJul 20, 2026

CVE-2026-64620

FreeRDP before 3.28.0 (affected <=3.27.1) contains a heap-based buffer overflow in crypto_rsa_common() (libfreerdp/crypto/crypto.c). The fun

CVSS

9.8

Critical

EPSS

—

KEV

—

Exploit Today

0-100

Published: Jul 20, 2026 · Last modified: Jul 20, 2026 · CWE-122

EPSS · 30d

Not enough EPSS history yet.

Technical description

FreeRDP 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.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-441788.8 HIG

—

——0xrdp is an open source RDP server. Versions 0.10.6 and prior contain a heap-based buffer overflow vulnerability within the virtual channel forwarding mechanism. When forwarding data from a remote client to the internal channel server, the xrdp process utilizes a fixed-size buffer without adequate bounds checking on the incoming payload. An authenticated remote attacker can exploit this flaw by sending a specially crafted virtual channel message that exceeds the buffer capacity, leading to heap memory corruption. This may result in a denial of service or the execution of arbitrary code with the privileges of the xrdp process. This issue has been fixed in version 0.10.6.1.18h CVE-2026-412529.8 CRI

—

——0xrdp is an open source RDP server. Versions 0.10.6 and prior contain a missing bounds check in xrdp, which allows a heap-based buffer overflow when operating in vnc-any mode. The issue occurs during the handling of RFB protocol color map messages from a VNC server, where incoming color indices are not properly validated. A malicious VNC server can exploit this flaw by sending crafted messages with out-of-range values, leading to an out-of-bounds write on the heap. This memory corruption can result in a denial of service (DoS) or potentially allow remote code execution (RCE) prior to authentication. This issue has been fixed in version 0.10.6.1.18h CVE-2026-35591—

—

——0libvips is a fast image processing library with low memory needs. The `tiffload` operation in libvips versions before and including 8.18.1 could incorrectly determine the number of channels in a JPEG or JPEG2000-encoded tile within a TIFF image, leading to a possible buffer overflow. This has been patched in version 8.18.2.19h CVE-2026-35590—

—

——0libvips is a fast image processing library with low memory needs. The EXIF decoder within libvips versions before and including 8.18.1 was not verifying the range of EXIF tag groups before passing data to libexif, leading to a possible null pointer dereference and crash. This has been patched in version 8.18.2.18h CVE-2026-630908.8 HIG

—

——0ProFTPD before 1.3.9c and 1.3.10rc3 contains a heap-based buffer overflow vulnerability in the mod_sftp module that allows authenticated low-privilege attackers to achieve arbitrary code execution by sending crafted SFTP packet fragments exceeding the 16 KB reassembly buffer in the fxp.c component. Attackers can supply oversized fragments to trigger an incorrectly conditioned reallocation, corrupt pool freelist metadata, overwrite the root_fs BSS global pointer to reference a fake filesystem struct, and redirect pr_fsio_stat() to system() via a crafted RENAME request.22h CVE-2026-539947.5 HIG

32.9%

——10ProFTPD mod_sftp contains a heap-based buffer overflow reachable by an authenticated SFTP user. The fxp_packet_read() function accepts the attacker-supplied 32-bit big-endian SFTP packet length without a minimum sanity check. A value of 0 causes an unsigned subtraction elsewhere in the read path to underflow to approximately 4 GB. That oversized request reaches the core memory allocator, where the rounded size is computed in size_t but passed to new_block() as a 32-bit int; the low 32 bits of 0x100000000 are 0, so new_block() returns a small (~512-byte) block while the caller is told it received ~4 GB. The subsequent fill loop then streams attacker-controlled bytes past the end of the 544-byte allocation, producing an attacker-controlled heap buffer overflow. An authenticated user can crash the per-connection ProFTPD session child on demand with a single malformed SFTP packet (packet_len=0 followed by a body greater than approximately 544 bytes), producing reliable authenticated remote denial of service. Depending on heap layout and adjacent allocations, heap metadata corruption and further consequences beyond denial of service may be possible, though only denial of service is demonstrated by the supplied proof of concept.3d