PatchTheCVECVE-2026-7829: UltraVNC repeater through 1.8.2.2 contains a post-authentication out-of-bounds write in the allow/deny rule pa
CVE-2026-7829 is a high-severity flaw (CVSS 7.2) affecting ultravnc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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
Why this priority
- High severity
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.2 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | High |
| User interaction | None |
| EPSS exploit chance | 0.9% (top 42%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2026-07-01 |
| Last modified | 2026-10-25 |
Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-7829?
ultravnc: upgrade to newer than 1.8.2.2. Exact commands for each OS are on this page.
Is CVE-2026-7829 being exploited?
CVE-2026-7829 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-7829 affect?
CVE-2026-7829 affects ultravnc. Severity is high (CVSS 7.2). 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/
How urgent is CVE-2026-7829?
Priority 40/100. High severity
Related CVEs
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- CVE-2026-7838 HIGH 8.8 UPGRADE UltraVNC viewer through 1.8.2.2 contains an integer overflow leading to a heap buffer overflow in the RFB prot
- CVE-2026-7839 CRITICAL 9.1 UPGRADE UltraVNC repeater through 1.8.2.2 initializes the HTTP administration server with a hardcoded default password
- CVE-2026-7828 MEDIUM 5.3 UPGRADE UltraVNC repeater through 1.8.2.2 contains an integer overflow in the HTTP request logging path
- CVE-2026-7831 HIGH 7.6 UPGRADE UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message han