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.
References
| Link | Resource |
|---|---|
| https://github.com/FreeRDP/FreeRDP/commit/1f7a716d39b5605bb8a83b0c3c97a6ce386609ef | Patch |
| https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-pjqx-v446-x7fc | Exploit Mitigation Vendor Advisory |
| https://www.vulncheck.com/advisories/freerdp-before-heap-buffer-overflow-via-crypto-rsa-common | Patch Third Party Advisory |
Configurations
History
28 Jul 2026, 15:38
| Type | Values Removed | Values Added |
|---|---|---|
| First Time |
Freerdp
Freerdp freerdp |
|
| CPE | cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* | |
| References | () https://github.com/FreeRDP/FreeRDP/commit/1f7a716d39b5605bb8a83b0c3c97a6ce386609ef - Patch | |
| References | () https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-pjqx-v446-x7fc - Exploit, Mitigation, Vendor Advisory | |
| References | () https://www.vulncheck.com/advisories/freerdp-before-heap-buffer-overflow-via-crypto-rsa-common - Patch, Third Party Advisory |
20 Jul 2026, 12:19
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-07-20 12:19
Updated : 2026-07-28 15:38
NVD link : CVE-2026-64620
Mitre link : CVE-2026-64620
CVE.ORG link : CVE-2026-64620
JSON object : View
Products Affected
freerdp
- freerdp
CWE
CWE-122
Heap-based Buffer Overflow