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CVE-2026-33977

FreeRDP: DoS via WINPR_ASSERT in IMA ADPCM audio decoder (dsp.c:331)

Published: Mar 30, 2026Updated: Apr 1, 2026 Sources: CVE List NVD BDUCWE-617
NVD MITRE
6.5CVSSMEDIUM
EPSS Score
0.3%
Top 83.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:RS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-617

Affected Products

АЛЬТ СП 10АО «ИВК»
On-premOS
Operating Systems / linux-distro
FreeRDPFree Software Foundation, Inc.OSS Libraries
FreeRDPFreeRDPOSS Libraries
freerdpfreerdpOSS Libraries
ао «ивк»commercialRUOperating Systemsaka ivk
free software foundation, inc.oss-projectUSOSS Librariesaka fsf, free software foundation
freerdposs-projectUSOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available
Workaround Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-8f2g-3q27-6xm5
github.com
https://altsp.su/obnovleniya-bezopasnosti/
altsp.su
https://github.com/FreeRDP/FreeRDP/commit/9be3f03d94a50892fd58a9f7dee72b2313c69b47
github.com

Timeline

Published
Mar 30, 2026
Last Updated
Apr 1, 2026

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