Client crash via zero ADPCM block alignment
Published Mar 13, 2026 · Updated Mar 13, 2026
Divide by zero in FreeRDP before 3.24.0 allows remote attackers to crash a client through a malicious RDPSND Server Audio Formats PDU. The MS-ADPCM and IMA-ADPCM decoders in libfreerdp/codec/dsp.c apply a modulo operation using unvalidated nBlockAlign as the divisor, so a zero value raises SIGFPE. A client must connect to a malicious RDP server and negotiate the affected audio path; the crafted format then terminates that client without further user interaction.
Summary
What happened
Divide by zero in FreeRDP before 3.24.0 allows remote attackers to crash a client through a malicious RDPSND Server Audio Formats PDU. The MS-ADPCM and IMA-ADPCM decoders in libfreerdp/codec/dsp.c apply a modulo operation using unvalidated nBlockAlign as the divisor, so a zero value raises SIGFPE. A client must connect to a malicious RDP server and negotiate the affected audio path; the crafted format then terminates that client without further user interaction.
The record
- CVE
- CVE-2026-31884
- Published
- Mar 13, 2026
- Updated
- Mar 13, 2026
- Vendor
- FreeRDP
- Product
- FreeRDP
- Classifications
- CWE-369, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 13, 2026CVE publishedPublication date reported by the CVE source.
- Mar 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 3.24.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Upstream ADPCM zero-block-alignment proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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