CVE-2019-20839 — libvncclient/sockets

libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.

01What is this vulnerability?

libvncclient/sockets.c in LibVNCServer before 0.9.13 has a buffer overflow via a long socket filename.

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

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2020-06-17T15:11:26.000Z
• Last modified: 2024-08-05T02:53:09.275Z

09References

• github.com — https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServe…
• github.com — https://github.com/LibVNC/libvncserver/commit/3fd03977c9b35800d73a865f167338cb4d…
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2020/06/msg00035.html
• lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro…
• lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro…
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.html
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.html
• lists.opensuse.org — http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.html
• usn.ubuntu.com — https://usn.ubuntu.com/4434-1/
• lists.debian.org — https://lists.debian.org/debian-lts-announce/2020/08/msg00045.html
• cert-portal.siemens.com — https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf