How severe is CVE-2009-0388?

CVE-2009-0388 has a CVSS 2.0 base score of 10.0, rated critical severity.

Is CVE-2009-0388 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-0388?

CVE-2009-0388 primarily affects Tightvnc. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-0388?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2009-0388 published?

CVE-2009-0388 was published on 2009-02-04 and last updated on 2026-06-16.

CVE-2009-0388

CVE-2009-0388 is a critical-severity vulnerability in Tightvnc with a CVSS 2.0 base score of 10.0. Its EPSS exploit-prediction score of 13% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-189.

Key facts

Severity: Critical (CVSS 2.0 base score 10.0)
EPSS exploit prediction: 13% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-189
Affected product: Tightvnc
Published: 2009-02-04
Last modified: 2026-06-16

Description

Multiple integer signedness errors in (1) UltraVNC 1.0.2 and 1.0.5 and (2) TightVnc 1.3.9 allow remote VNC servers to cause a denial of service (heap corruption and application crash) or possibly execute arbitrary code via a large length value in a message, related to the (a) ClientConnection::CheckBufferSize and (b) ClientConnection::CheckFileZipBufferSize functions in ClientConnection.cpp.

Frequently asked questions

What is CVE-2009-0388?: Multiple integer signedness errors in (1) UltraVNC 1.0.2 and 1.0.5 and (2) TightVnc 1.3.9 allow remote VNC servers to cause a denial of service (heap corruption and application crash) or possibly execute arbitrary code via a large length value in a message, related to the (a) ClientConnection::CheckBufferSize and (b) ClientConnection::CheckFileZipBufferSize functions in ClientConnection.cpp.
How severe is CVE-2009-0388?: CVE-2009-0388 has a CVSS 2.0 base score of 10.0, rated critical severity.
Is CVE-2009-0388 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-0388?: CVE-2009-0388 primarily affects Tightvnc. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-0388?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2009-0388 published?: CVE-2009-0388 was published on 2009-02-04 and last updated on 2026-06-16.

References

Affected products (3)

cpe:2.3:a:tightvnc:tightvnc:1.3.9:*:*:*:*:*:*:*
cpe:2.3:a:ultravnc:ultravnc:1.0.2:*:*:*:*:*:*:*
cpe:2.3:a:ultravnc:ultravnc:1.0.5:*:*:*:*:*:*:*

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