It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames.
It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames. A malicious attacker could exploit this by sending specially crafted WebSocket frames to a server, causing a heap-based buffer overflow.
- Published
- Jun 30, 2020
- Updated
- Jun 16, 2026
- EPSS
- 2.3% · 82th percentile
- CWE
- CWE-787
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Report tools
Action score
40
Plan
Add it to your regular patch cycle.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.3%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| libvncserver project | libvncserver | cpe:2.3:a:libvncserver_project:libvncserver |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| opensuse | leap | cpe:2.3:o:opensuse:leap |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| siemens | simatic itc1500 firmware | cpe:2.3:o:siemens:simatic_itc1500_firmware |
| siemens | simatic itc1500 | cpe:2.3:h:siemens:simatic_itc1500 |
| siemens | simatic itc1500 pro firmware | cpe:2.3:o:siemens:simatic_itc1500_pro_firmware |
| siemens | simatic itc1500 pro | cpe:2.3:h:siemens:simatic_itc1500_pro |
| siemens | simatic itc1900 firmware | cpe:2.3:o:siemens:simatic_itc1900_firmware |
| siemens | simatic itc1900 | cpe:2.3:h:siemens:simatic_itc1900 |
| siemens | simatic itc1900 pro firmware | cpe:2.3:o:siemens:simatic_itc1900_pro_firmware |
| siemens | simatic itc1900 pro | cpe:2.3:h:siemens:simatic_itc1900_pro |
and 4 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux16.04
- canonical ubuntu linux18.04
- canonical ubuntu linux19.10
- canonical ubuntu linux20.04
- fedoraproject fedora31
- fedoraproject fedora32
- libvncserver project libvncserverbefore 0.9.12
- opensuse leap15.1
- opensuse leap15.2
- siemens simatic itc1500 firmware3.0.0.0 and later · before 3.2.1.0
- siemens simatic itc1500 pro firmware3.0.0.0 and later · before 3.2.1.0
- siemens simatic itc1900 firmware3.0.0.0 and later · before 3.2.1.0
- siemens simatic itc1900 pro firmware3.0.0.0 and later · before 3.2.1.0
- siemens simatic itc2200 firmware3.0.0.0 and later · before 3.2.1.0
- siemens simatic itc2200 pro firmware3.0.0.0 and later · before 3.2.1.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | libvncserver-devel | before 0.9.11-15.el8_2.1 | 0.9.11-15.el8_2.1 |
| Debian:12 | libvncserver | before 0.9.12+dfsg-3 | 0.9.12+dfsg-3 |
| openSUSE:Leap 15.1 | LibVNCServer | before 0.9.10-lp151.7.9.1 | 0.9.10-lp151.7.9.1 |
| openSUSE:Leap 15.1 | LibVNCServer | before 0.9.10-lp151.7.6.1 | 0.9.10-lp151.7.6.1 |
| openSUSE:Leap 15.2 | LibVNCServer | before 0.9.10-lp152.9.4.2 | 0.9.10-lp152.9.4.2 |
| openSUSE:Leap 15.2 | LibVNCServer | before 0.9.10-lp152.9.4.1 | 0.9.10-lp152.9.4.1 |
| openSUSE:Leap 15.2 | LibVNCServer | before 0.9.10-lp152.9.8.1 | 0.9.10-lp152.9.8.1 |
| Red Hat:enterprise_linux:7::client | libvncserver | before 0:0.9.9-14.el7_8.1 | 0:0.9.9-14.el7_8.1 |
| Red Hat:enterprise_linux:7::client | libvncserver-debuginfo | before 0:0.9.9-14.el7_8.1 | 0:0.9.9-14.el7_8.1 |
| Red Hat:enterprise_linux:7::client | libvncserver-devel | before 0:0.9.9-14.el7_8.1 | 0:0.9.9-14.el7_8.1 |
| Red Hat:enterprise_linux:8::appstream | libvncserver | before 0:0.9.11-15.el8_2.1 | 0:0.9.11-15.el8_2.1 |
| Red Hat:enterprise_linux:8::appstream | libvncserver-debuginfo | before 0:0.9.11-15.el8_2.1 | 0:0.9.11-15.el8_2.1 |
| Red Hat:enterprise_linux:8::appstream | libvncserver-debugsource | before 0:0.9.11-15.el8_2.1 | 0:0.9.11-15.el8_2.1 |
| Red Hat:enterprise_linux:8::crb | libvncserver-devel | before 0:0.9.11-15.el8_2.1 | 0:0.9.11-15.el8_2.1 |
| Red Hat:rhel_e4s:8.0::appstream | libvncserver | before 0:0.9.11-9.el8_0.3 | 0:0.9.11-9.el8_0.3 |
| Red Hat:rhel_e4s:8.0::appstream | libvncserver-debuginfo | before 0:0.9.11-9.el8_0.3 | 0:0.9.11-9.el8_0.3 |
| Red Hat:rhel_e4s:8.0::appstream | libvncserver-debugsource | before 0:0.9.11-9.el8_0.3 | 0:0.9.11-9.el8_0.3 |
| Red Hat:rhel_eus:8.1::appstream | libvncserver | before 0:0.9.11-9.el8_1.3 | 0:0.9.11-9.el8_1.3 |
| Red Hat:rhel_eus:8.1::appstream | libvncserver-debuginfo | before 0:0.9.11-9.el8_1.3 | 0:0.9.11-9.el8_1.3 |
| Red Hat:rhel_eus:8.1::appstream | libvncserver-debugsource | before 0:0.9.11-9.el8_1.3 | 0:0.9.11-9.el8_1.3 |
| Red Hat:rhel_eus:8.1::crb | libvncserver-devel | before 0:0.9.11-9.el8_1.3 | 0:0.9.11-9.el8_1.3 |
| SUSE:HPE Helion OpenStack 8 | LibVNCServer | before 0.9.9-17.31.1 | 0.9.9-17.31.1 |
| SUSE:Linux Enterprise Module for Package Hub 15 SP1 | LibVNCServer | before 0.9.10-4.19.1 | 0.9.10-4.19.1 |
| SUSE:Linux Enterprise Module for Package Hub 15 SP1 | LibVNCServer | before 0.9.10-4.22.1 | 0.9.10-4.22.1 |
Same product
libvncserver project: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-7225An issue was discovered in LibVNCServer through 0.9.11.41Plan
- CVE-2016-9942Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (appl40Plan
- CVE-2016-9941Heap-based buffer overflow in rfbproto.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (a40Plan
- CVE-2020-14400An issue was discovered in LibVNCServer before 0.9.13.31Monitor
- CVE-2020-14399An issue was discovered in LibVNCServer before 0.9.13.31Monitor
- CVE-2010-5304A NULL pointer dereference flaw was found in the way LibVNCServer before 0.9.9 handled certain ClientCutText message.31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:libvncserver-devel | 0.9.11-15.el8_2.1 · AlmaLinux:8 | Package registry (OSV) |
| debian:libvncserver | 0.9.12+dfsg-3 · Debian:12 | Package registry (OSV) |
| opensuse:LibVNCServer | 0.9.10-lp151.7.6.1 · openSUSE:Leap 15.1 | Package registry (OSV) |
| red hat:libvncserver | 0:0.9.9-14.el7_8.1 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libvncserver-debuginfo | 0:0.9.9-14.el7_8.1 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libvncserver-debugsource | 0:0.9.11-15.el8_2.1 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:libvncserver-devel | 0:0.9.9-14.el7_8.1 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:LibVNCServer | 0.9.10-4.19.1 · SUSE:Linux Enterprise Module for Package Hub 15 SP1 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00020.html
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00028.html
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.html
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.html
- lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.html
- www.openwall.com/lists/oss-security/2020/06/30/3
- bugzilla.redhat.com/show_bug.cgi?id=1852356
- cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf
- github.com/LibVNC/libvncserver/commit/aac95a9dcf4bbba87b76c72706c3221a842ca433
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4F6FUH4EFK4NAP6GT4TQRTBKWIRCZLIY/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NVP7TJVYJDXDFRHVQ3ENEN3H354QPXEZ/
- usn.ubuntu.com/4407-1/
- www.openwall.com/lists/oss-security/2020/06/30/2
Vendor advisories and official records. Exploit/PoC links are deliberately left out.