How severe is CVE-2016-7943?

CVE-2016-7943 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-7943 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-7943?

CVE-2016-7943 primarily affects X.org Libx11. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-7943?

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-2016-7943 published?

CVE-2016-7943 was published on 2016-12-13 and last updated on 2026-06-17.

CVE-2016-7943

CVE-2016-7943 is a critical-severity vulnerability in X.org Libx11 with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: X.org Libx11
Published: 2016-12-13
Last modified: 2026-06-17

Description

The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.

Frequently asked questions

What is CVE-2016-7943?: The XListFonts function in X.org libX11 before 1.6.4 might allow remote X servers to gain privileges via vectors involving length fields, which trigger out-of-bounds write operations.
How severe is CVE-2016-7943?: CVE-2016-7943 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-7943 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-7943?: CVE-2016-7943 primarily affects X.org Libx11. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-7943?: 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-2016-7943 published?: CVE-2016-7943 was published on 2016-12-13 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:fedoraproject:fedora:25:*:*:*:*:*:*:*
cpe:2.3:a:x.org:libx11:*:*:*:*:*:*:*:*

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