Client CPU hang via wrapped quantization subtraction
Published Mar 30, 2026 · Updated Mar 30, 2026
Integer wraparound in FreeRDP before 3.24.2 allows remote attackers to hang an RDP client through crafted progressive-codec data. The progressive_decompress_tile_upgrade() path continues after a quantization mismatch, then subtracts larger BYTE values without validation and uses the wrapped value 247 as a shift exponent in an approximately 80 billion-iteration loop. Exploitation requires a user to connect the client to attacker-controlled RDP content; the demonstrated consequence is a complete CPU hang without memory corruption.
Summary
What happened
Integer wraparound in FreeRDP before 3.24.2 allows remote attackers to hang an RDP client through crafted progressive-codec data. The progressive_decompress_tile_upgrade() path continues after a quantization mismatch, then subtracts larger BYTE values without validation and uses the wrapped value 247 as a shift exponent in an approximately 80 billion-iteration loop. Exploitation requires a user to connect the client to attacker-controlled RDP content; the demonstrated consequence is a complete CPU hang without memory corruption.
The record
- CVE
- CVE-2026-33983
- Published
- Mar 30, 2026
- Updated
- Mar 30, 2026
- Vendor
- FreeRDP
- Product
- FreeRDP
- Classifications
- CWE-190, CWE-252, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 30, 2026CVE publishedPublication date reported by the CVE source.
- Mar 30, 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=< 3.24.2
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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