CVE-2018-20748 — LibVNC before 0

LibVNC before 0.9.12 contains multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c. The fix for CVE-2018-20019 was incomplete.

01What is this vulnerability?

LibVNC before 0.9.12 contains multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c. The fix for CVE-2018-20019 was incomplete.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

08Timeline

• Published: 2019-01-30T18:00:00.000Z
• Last modified: 2024-08-05T12:12:28.501Z

09References

• lists.debian.org — https://lists.debian.org/debian-lts-announce/2019/01/msg00029.html
• github.com — https://github.com/LibVNC/libvncserver/commit/a64c3b37af9a6c8f8009d7516874b8d266…
• github.com — https://github.com/LibVNC/libvncserver/commit/e34bcbb759ca5bef85809967a268fdf214…
• github.com — https://github.com/LibVNC/libvncserver/issues/273
• github.com — https://github.com/LibVNC/libvncserver/commit/c5ba3fee85a7ecbbca1df5ffd46d32b927…
• github.com — https://github.com/LibVNC/libvncserver/commit/c2c4b81e6cb3b485fb1ec7ba9e7defeb88…
• usn.ubuntu.com — https://usn.ubuntu.com/3877-1/
• www.openwall.com — https://www.openwall.com/lists/oss-security/2018/12/10/8
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
• usn.ubuntu.com — https://usn.ubuntu.com/4547-1/
• usn.ubuntu.com — https://usn.ubuntu.com/4587-1/
• cert-portal.siemens.com — https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf