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CVE-2026-33977— FreeRDP: DoS via WINPR_ASSERT in IMA ADPCM audio decoder (dsp.c:331)

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，该漏洞源于恶意RDP服务器发送具有无效初始步进索引值的IMA ADPCM格式音频数据，触发断言失败和进程中止，可能导致启用音频重定向的FreeRDP客户端崩溃。

AI Predicted 5.3 Difficulty: Easy EPSS 0.39% · P31
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I. Basic Information for CVE-2026-33977

Vulnerability Information
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Vulnerability Title
FreeRDP: DoS via WINPR_ASSERT in IMA ADPCM audio decoder (dsp.c:331)
Source: CVE Program / CVE List V5
Vulnerability Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, a malicious RDP server can crash the FreeRDP client by sending audio data in IMA ADPCM format with an invalid initial step index value (>= 89). The unvalidated step index is read directly from the network and used to index into a 89-entry lookup table, triggering a WINPR_ASSERT() failure and process abort via SIGABRT. This affects any FreeRDP client that has audio redirection (RDPSND) enabled, which is the default configuration. This issue has been patched in version 3.24.2.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
可达断言
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，该漏洞源于恶意RDP服务器发送具有无效初始步进索引值的IMA ADPCM格式音频数据，触发断言失败和进程中止，可能导致启用音频重定向的FreeRDP客户端崩溃。
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-2026-33977

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III. Intelligence Information for CVE-2026-33977

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Vendor Advisories for CVE-2026-33977 (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-2026-33983 6.5 MEDIUM FreeRDP: Progressive Codec Quant BYTE Underflow - UB + CPU DoS
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-2026-33952 FreeRDP: DoS via WINPR_ASSERT in rts_read_auth_verifier_no_checks

IV. Related Vulnerabilities

Same product: FreeRDP
Same vendor: FreeRDP
Same weakness: CWE-617

V. Comments for CVE-2026-33977

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