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CVE-2026-109952— FreeRDP 3.0.0 before 3.32.0 Security Protocol Downgrade via Negotiation Response

Quick assessment

Affected
FreeRDP FreeRDP
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

FreeRDP 客户端在 3.32.0 版本之前的 3.0.0 至 3.32.0 版本中，在 函数中未对服务器选择的 PROTOCOL_RDSTLS 或 PROTOCOL_HYBRID_EX 协议进行与已启用协议集的匹配检查，从而导致安全协议降级漏洞。攻击者（恶意服务器或中间人）可选择 RDSTLS 协议以覆盖 /sec:nla 的安全锁定设置，并使用全零 Cookie 完成身份验证，进而在 Client Info PDU 中获取用户的明文密码。

CVSS 5.3 · Medium EPSS 0.26% · P16

Affected Version Matrix 2

VendorProduct Version RangeStatus
FreeRDP FreeRDP 3.0.0< 3.32.0 affected
3.32.0 unaffected
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I. Basic Information for CVE-2026-109952

Vulnerability Information
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Vulnerability Title
FreeRDP 3.0.0 before 3.32.0 Security Protocol Downgrade via Negotiation Response
Source: CVE Program / CVE List V5
Vulnerability Description
The FreeRDP client 3.0.0 before 3.32.0 does not check a server-selected PROTOCOL_RDSTLS or PROTOCOL_HYBRID_EX against its enabled protocol set in nego_process_negotiation_response(), allowing a security protocol downgrade. A malicious server or man-in-the-middle can select RDSTLS to override /sec:nla pinning, complete authentication with an all-zero cookie, and receive the user's cleartext password in the Client Info PDU.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
在会话协商时选择低安全性的算法(算法降级)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
FreeRDP FreeRDP 3.0.0 ~ 3.32.0 -

II. Public POCs for CVE-2026-109952

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III. Intelligence Information for CVE-2026-109952

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Vendor Advisories for CVE-2026-109952 (1)

News Coverage for CVE-2026-109952 (1)

Same Patch Batch · FreeRDP · 2026-10-13 · 21 CVEs total

CVE-2026-109676 8.8 HIGH FreeRDP 3.0.0-beta1 before 3.32.0 Use-After-Free via Smartcard Connect
CVE-2026-109678 6.5 MEDIUM FreeRDP 3.0.0-beta1 before 3.32.0 Reachable Assertion via Emulated SCardStatusA
CVE-2026-109677 6.5 MEDIUM FreeRDP 2.0.0-beta1 before 3.28.0 Out-of-Bounds Read via LocateCardsByATRA Handler
CVE-2026-109942 6.5 MEDIUM FreeRDP 2.3.0 before 3.32.0 NULL Pointer Dereference via RD Gateway Close Channel Packet
CVE-2026-109941 6.5 MEDIUM FreeRDP 2.3.0 before 3.32.0 Infinite Loop via RD Gateway Chunked Response
CVE-2026-109938 6.5 MEDIUM FreeRDP 3.11.0 before 3.32.0 Integer Overflow via Mapped Video Geometry Update
CVE-2026-109946 6.5 MEDIUM FreeRDP 3.11.0 before 3.32.0 Reachable Assertion via AVC444 Odd Region Width
CVE-2026-109944 6.5 MEDIUM FreeRDP 3.0.0 before 3.32.0 Reachable Assertion via Stale Smartcard Handle
CVE-2026-109939 6.5 MEDIUM FreeRDP 3.27.1 before 3.32.0 NULL Pointer Dereference via Cache Bitmap V3 Order
CVE-2026-109943 6.5 MEDIUM FreeRDP 3.29.0 before 3.32.0 Double Free via Async-Update Polygon Order
CVE-2026-109947 6.5 MEDIUM FreeRDP 3.20.1 before 3.32.0 Unbounded Allocation via drive_process_irp_read
CVE-2026-109949 6.5 MEDIUM FreeRDP 3.0.0 before 3.32.0 PIN Brute-Force via Virtual Smartcard
CVE-2026-109953 5.3 MEDIUM FreeRDP 3.0.0 before 3.32.0 Cleartext Credential Disclosure via /restricted-admin
CVE-2026-109680 5.3 MEDIUM FreeRDP 3.18.0 before 3.32.0 Heap Out-of-Bounds Write via ARM Redirected Username
CVE-2026-109945 5.3 MEDIUM FreeRDP 3.0.0 before 3.32.0 Smartcard Use-After-Free via Concurrent Disconnect and Transmi
CVE-2026-109679 5.3 MEDIUM FreeRDP 3.0.0-beta4 before 3.32.0 NULL Pointer Crash via ARM Response
CVE-2026-109951 5.3 MEDIUM FreeRDP 3.17.1 before 3.32.0 Heap Buffer Over-Read via Proxy DRDYNVC Channel Name
CVE-2026-109940 4.3 MEDIUM FreeRDP 3.0.0-beta1 before 3.32.0 Stack Buffer Overflow via PKCS#11 Key Name
CVE-2026-109948 4.3 MEDIUM FreeRDP 3.0.0 before 3.32.0 Memory Disclosure via SCardTransmit Smartcard Redirection
CVE-2026-109950 4.3 MEDIUM FreeRDP 3.0.0 before 3.32.0 Heap Out-of-Bounds Read via RD Gateway Messages

IV. Related Vulnerabilities

Same product: FreeRDP
Same vendor: FreeRDP
Same weakness: CWE-757

V. Comments for CVE-2026-109952

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