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CVE-2026-33983— FreeRDP: Progressive Codec Quant BYTE Underflow - UB + CPU DoS

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是FreeRDP团队的一款开源的远程桌面协议（RDP）的实现。 FreeRDP 3.24.2之前版本存在安全漏洞，该漏洞源于progressive_decompress_tile_upgrade函数检测到不匹配后仅发出警告并继续执行，导致使用包装值作为移位指数，可能引发未定义行为和CPU拒绝服务攻击。

CVSS 6.5 · Medium EPSS 0.80% · P55

Affected Version Matrix 1

VendorProduct Version RangeStatus
FreeRDP FreeRDP < 3.24.2 affected
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I. Basic Information for CVE-2026-33983

Vulnerability Information
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Vulnerability Title
FreeRDP: Progressive Codec Quant BYTE Underflow - UB + CPU DoS
Source: CVE Program / CVE List V5
Vulnerability Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, progressive_decompress_tile_upgrade() detects a mismatch via progressive_rfx_quant_cmp_equal() but only emits WLog_WARN, execution continues. The wrapped value (247) is used as a shift exponent, causing undefined behavior and an approximately 80 billion iteration loop (CPU DoS). This issue has been patched in version 3.24.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
整数溢出或超界折返
Source: CVE Program / CVE List V5
Vulnerability Title
FreeRDP 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FreeRDP是FreeRDP团队的一款开源的远程桌面协议（RDP）的实现。 FreeRDP 3.24.2之前版本存在安全漏洞，该漏洞源于progressive_decompress_tile_upgrade函数检测到不匹配后仅发出警告并继续执行，导致使用包装值作为移位指数，可能引发未定义行为和CPU拒绝服务攻击。
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 < 3.24.2 -

II. Public POCs for CVE-2026-33983

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III. Intelligence Information for CVE-2026-33983

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Vendor Advisories for CVE-2026-33983 (1)

Same Patch Batch · FreeRDP · 2026-03-30 · 9 CVEs total

CVE-2026-33984 7.5 HIGH FreeRDP: ClearCodec resize_vbar_entry() Heap OOB Write
CVE-2026-33986 7.5 HIGH FreeRDP: H.264 YUV Buffer Dimension Desync - Heap OOB Write
CVE-2026-33982 7.1 HIGH FreeRDP: Persistent Cache Allocator Mismatch - Heap OOB Read
CVE-2026-33987 7.1 HIGH FreeRDP: Persistent Cache bmpSize Desync - Heap OOB Write
CVE-2026-33985 5.9 MEDIUM FreeRDP: ClearCodec Glyph Cache Count Desync - Heap OOB Read
CVE-2026-33995 5.3 MEDIUM FreeRDP: Possible double free in kerberos_AcceptSecurityContext
CVE-2026-33977 FreeRDP: DoS via WINPR_ASSERT in IMA ADPCM audio decoder (dsp.c:331)
CVE-2026-33952 FreeRDP: DoS via WINPR_ASSERT in rts_read_auth_verifier_no_checks

IV. Related Vulnerabilities

Same product: FreeRDP
Same vendor: FreeRDP
Same weakness: CWE-190

V. Comments for CVE-2026-33983

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