The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer 0.9.9 and earlier does not check certain malloc return values
The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer 0.9.9 and earlier does not check certain malloc return values, which allows remote VNC servers to cause a denial of service (application crash) or possibly execute arbitrary code by specifying a large screen size in a (1) FramebufferUpdate, (2) ResizeFrameBuffer, or (3) PalmVNCReSizeFrameBuffer message.
- Published
- Dec 15, 2014
- Updated
- Jun 16, 2026
- EPSS
- 6.8% · 94th percentile
- CWE
- CWE-20
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Report tools
Action score
32
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 2 / 30 · 6.8%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| libvncserver | libvncserver | cpe:2.3:a:libvncserver:libvncserver |
| oracle | solaris | cpe:2.3:o:oracle:solaris |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux12.04
- canonical ubuntu linux14.04
- debian debian linux7.0
- libvncserver libvncserverup to 0.9.9 inclusive
- oracle solaris11.3
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | libvncserver | before 0.9.9+dfsg-6.1 | 0.9.9+dfsg-6.1 |
| Debian:12 | veyon | before 4.1.4+repack1-1 | 4.1.4+repack1-1 |
| Debian:6.0 | libvncserver | before 0.9.7-2+deb6u1 | 0.9.7-2+deb6u1 |
| Debian:7 | libvncserver | before 0.9.9+dfsg-1+deb7u1 | 0.9.9+dfsg-1+deb7u1 |
| Debian:8 | italc | before 1:2.0.2+dfsg1-2+deb8u1 | 1:2.0.2+dfsg1-2+deb8u1 |
| Red Hat:enterprise_linux:6::client | libvncserver | before 0:0.9.7-7.el6_6.1 | 0:0.9.7-7.el6_6.1 |
| Red Hat:enterprise_linux:6::client | libvncserver-debuginfo | before 0:0.9.7-7.el6_6.1 | 0:0.9.7-7.el6_6.1 |
| Red Hat:enterprise_linux:6::client | libvncserver-devel | before 0:0.9.7-7.el6_6.1 | 0:0.9.7-7.el6_6.1 |
| Red Hat:enterprise_linux:7::client | libvncserver | before 0:0.9.9-9.el7_0.1 | 0:0.9.9-9.el7_0.1 |
| Red Hat:enterprise_linux:7::client | libvncserver-debuginfo | before 0:0.9.9-9.el7_0.1 | 0:0.9.9-9.el7_0.1 |
| Red Hat:enterprise_linux:7::client | libvncserver-devel | before 0:0.9.9-9.el7_0.1 | 0:0.9.9-9.el7_0.1 |
| SUSE:Linux Enterprise Desktop 12 | LibVNCServer | before 0.9.9-16.1 | 0.9.9-16.1 |
| SUSE:Linux Enterprise Software Development Kit 11 SP3 | LibVNCServer | before 0.9.1-156.1 | 0.9.1-156.1 |
Same product
libvncserver: all recordsOther highest-scoring records for the same primary product.
- CVE-2014-6051Integer overflow in the MallocFrameBuffer function in vncviewer.c in LibVNCServer 0.9.9 and earlier allows remote VNC servers to cause a den32Monitor
- CVE-2006-2450auth.c in LibVNCServer 0.7.1 allows remote attackers to bypass authentication via a request in which the client specifies an insecure securi31Monitor
- CVE-2014-6055Multiple stack-based buffer overflows in the File Transfer feature in rfbserver.c in LibVNCServer 0.9.9 and earlier allow remote authenticat28Monitor
- CVE-2014-6053The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer 0.9.9 and earlier does not properly handle attempts t22Monitor
- CVE-2014-6054The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer 0.9.9 and earlier allows remote attackers to cause a 19Monitor
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 |
|---|---|---|
| debian:italc | 1:2.0.2+dfsg1-2+deb8u1 · Debian:8 | Package registry (OSV) |
| debian:libvncserver | 0.9.9+dfsg-6.1 · Debian:12 | Package registry (OSV) |
| debian:veyon | 4.1.4+repack1-1 · Debian:12 | Package registry (OSV) |
| red hat:libvncserver | 0:0.9.7-7.el6_6.1 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:libvncserver-debuginfo | 0:0.9.7-7.el6_6.1 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| red hat:libvncserver-devel | 0:0.9.7-7.el6_6.1 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| suse:LibVNCServer | 0.9.9-16.1 · SUSE:Linux Enterprise Desktop 12 | 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.
No commit or PR link among the references.
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
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- P · data can be read
- Integrity
- P · data or configuration can be modified
- Availability
- P · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- P
- Integrity impact
- P
- Availability impact
- P
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
AV:N/AC:L/Au:N/C:P/I:P/A:P
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.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
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-updates/2015-12/msg00022.html
- seclists.org/oss-sec/2014/q3/639
- secunia.com/advisories/61506
- secunia.com/advisories/61682
- ubuntu.com/usn/usn-2365-1
- www.debian.org/security/2014/dsa-3081
- www.ocert.org/advisories/ocert-2014-007.html
- www.openwall.com/lists/oss-security/2014/09/25/11
- www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
- www.securityfocus.com/bid/70091
- lists.debian.org/debian-lts-announce/2019/10/msg00042.html
- security.gentoo.org/glsa/201507-07
- usn.ubuntu.com/4587-1/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.