TI-2026-26318 Aliases CVE-2026-33977

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

MEDIUM 64CWE-617Published 2026-03-30 · Updated 2026-03-31

Key facts

Attack vector: Network
Privileges required: None
User interaction: Active
Attack complexity: Low
Attack requirements: None
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 5 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-617.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00266 18th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Partial FreeRDP (FreeRDP): 3.24.2Red Hat: 5 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
FreeRDP	FreeRDP	before 3.24.2	3.24.2	Patch available	CNA

FreeRDP VendorFreeRDP Affected before 3.24.2 Fixed in 3.24.2 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:freerdp:freerdp::::::::	before 3.24.2	Vulnerable	FreeRDP

cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* Versions before 3.24.2 Vulnerable ·FreeRDP

Remediation

Fix · CNA FreeRDP (FreeRDP) Fixed in 3.24.2

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 7	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 8	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-33977

References

Exploit 1

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-8f2g-3q27-6xm5

Patch 1

https://github.com/FreeRDP/FreeRDP/commit/9be3f03d94a50892fd58a9f7dee72b2313c69b47

TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handling CVSS 4.0CRITICAL 9.3
TI-2026-85091 Out-of-bounds write in FreeRDP proxy via bitmap cache v2 capability CVSS 4.0CRITICAL 9.3
TI-2026-24435 FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write CVSS 3.1CRITICAL 9.8
TI-2023-21373 Out-Of-Bounds Write in FreeRDP CVSS 3.1CRITICAL 9.8
TI-2022-08692 Server side NTLM does not properly check parameters in FreeRDP CVSS 3.1CRITICAL 9.1
TI-2023-21374 Out-Of-Bounds Read in FreeRDP CVSS 3.1CRITICAL 9.1

See all 336 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences