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CVE-2026-64620— FreeRDP before 3.28.0 Heap Buffer Overflow via crypto_rsa_common

Quick assessment

Affected
FreeRDP FreeRDP
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

FreeRDP是FreeRDP团队开源的一款开源的远程桌面协议(RDP)的实现。 FreeRDP 3.28.0之前版本存在缓冲区错误漏洞，该漏洞源于crypto_rsa_common()函数中存在堆缓冲区溢出，可能导致未经身份验证的攻击者伪造密文造成拒绝服务。

CVSS 9.8 · Critical EPSS 0.91% · P58

Affected Version Matrix 2

VendorProduct Version RangeStatus
FreeRDP FreeRDP < 3.28.0 affected
3.28.0 unaffected
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I. Basic Information for CVE-2026-64620

Vulnerability Information
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Vulnerability Title
FreeRDP before 3.28.0 Heap Buffer Overflow via crypto_rsa_common
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
堆缓冲区溢出
Source: CVE Program / CVE List V5
Vulnerability Title
FreeRDP 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FreeRDP是FreeRDP团队开源的一款开源的远程桌面协议(RDP)的实现。 FreeRDP 3.28.0之前版本存在缓冲区错误漏洞，该漏洞源于crypto_rsa_common()函数中存在堆缓冲区溢出，可能导致未经身份验证的攻击者伪造密文造成拒绝服务。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
FreeRDP FreeRDP 0 ~ 3.28.0 -

II. Public POCs for CVE-2026-64620

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 14533 chars
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III. Intelligence Information for CVE-2026-64620

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Vendor Advisories for CVE-2026-64620 (2)

Same Patch Batch · FreeRDP · 2026-07-20 · 3 CVEs total

CVE-2026-64624 7.8 HIGH FreeRDP RDP File Parser Remote Code Execution via CLI Options
CVE-2026-64621 7.3 HIGH FreeRDP before 3.28.0 Double-Free via selectedmonitors

IV. Related Vulnerabilities

Same product: FreeRDP
Same vendor: FreeRDP
Same weakness: CWE-122

V. Comments for CVE-2026-64620

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