Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
FreeRDP before 3.28.0 Heap Buffer Overflow via crypto_rsa_common
AV AC AT PR UI VC VI VA CVSS EPSS %ile KEV
N L N N N H H H 9.3 .0085 55.4 —
AFFECTED
Product Versions Fixed
FreeRDP unspecified 3.28.0
TIMELINE
Jul 20 EXPLOIT PUBLISHED — CVE-2026-64620 (FreeRDP). Public exploit reference added.
Jul 20 Reserved by VulnCheck
Jul 20 Published (CNA: VulnCheck)
Jul 28 EXPLOIT PUBLISHED — CVE-2026-64620 (FreeRDP). Public exploit reference added.
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.
Lifecycle
Complete event history — 4 events, chronological
| Date | Event | Detail |
|---|
| July 20, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-64620 (FreeRDP). Public exploit reference added. |
| July 20, 2026 | Reserved | Reserved by VulnCheck |
| July 20, 2026 | Published | Published (CNA: VulnCheck) |
| July 28, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-64620 (FreeRDP). Public exploit reference added. |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| FreeRDP | FreeRDP | — | — | 3.28.0 |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-64620 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.