Latent heap overwrite via unchecked allocation arithmetic
Published Jul 1, 2026 · Updated Jul 1, 2026
Integer overflow in UltraVNC repeater through 1.8.2.2 creates a latent heap overwrite in HTTP request logging. In repeater/webgui/settings.c, win_log() adds an HTTP URI length to sizeof(struct LIST) without an overflow check, then copies the complete string into the allocation. Remote attackers need access to the repeater HTTP port, but the 153,600-byte receive limit keeps URI length far below SIZE_MAX, so the current HTTP path cannot reach the overflow.
Summary
What happened
Integer overflow in UltraVNC repeater through 1.8.2.2 creates a latent heap overwrite in HTTP request logging. In repeater/webgui/settings.c, win_log() adds an HTTP URI length to sizeof(struct LIST) without an overflow check, then copies the complete string into the allocation. Remote attackers need access to the repeater HTTP port, but the 153,600-byte receive limit keeps URI length far below SIZE_MAX, so the current HTTP path cannot reach the overflow.
The record
- CVE
- CVE-2026-7828
- Published
- Jul 1, 2026
- Updated
- Jul 1, 2026
- Vendor
- UltraVNC Team
- Product
- UltraVNC
- Classifications
- CWE-190, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 1, 2026CVE publishedPublication date reported by the CVE source.
- Jul 1, 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?
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- Affected versionversion=0 <=1.8.2.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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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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