CVE-2026-7829: UltraVNC repeater authenticated out-of-bounds write in rule parser via oversized token
uvnc · UltraVNC
Vendor fix available · Affected: uvnc UltraVNC · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 58% of scored CVEs
DescriptionCVE.org
UltraVNC repeater through 1.8.2.2 contains a post-authentication out-of-bounds write in the allow/deny rule parser. In repeater/webgui/settings.c:225-272, after strncpy_s copies a rule token into temp1[rule1] (25-byte destination) or temp2/temp3 (16-byte destination), the code unconditionally writes a NUL terminator at temp1[rule1][len] = 0 without clamping len to the destination size. When an authenticated administrator saves a rule with a token length equal to or greater than the destination size, the NUL byte is written one or more bytes past the end of the stack-allocated array, corrupting adjacent stack data. An attacker who has obtained admin credentials (including via CVE-2026-7839 default password) can trigger this to gain code execution on the repeater host.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- uvnc · UltraVNCup to and including 1.8.2.2
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-7829 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.