How severe is CVE-2016-6354?

CVE-2016-6354 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-2016-6354 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-6354?

CVE-2016-6354 primarily affects Westes Flex. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-6354?

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-2016-6354 published?

CVE-2016-6354 was published on 2016-09-21 and last updated on 2026-06-17.

CVE-2016-6354

CVE-2016-6354 is a critical-severity vulnerability in Westes Flex 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-119.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 9% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Westes Flex
Published: 2016-09-21
Last modified: 2026-06-17

Description

Heap-based buffer overflow in the yy_get_next_buffer function in Flex before 2.6.1 might allow context-dependent attackers to cause a denial of service or possibly execute arbitrary code via vectors involving num_to_read.

Frequently asked questions

What is CVE-2016-6354?: Heap-based buffer overflow in the yy_get_next_buffer function in Flex before 2.6.1 might allow context-dependent attackers to cause a denial of service or possibly execute arbitrary code via vectors involving num_to_read.
How severe is CVE-2016-6354?: CVE-2016-6354 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-2016-6354 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-6354?: CVE-2016-6354 primarily affects Westes Flex. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-6354?: 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-2016-6354 published?: CVE-2016-6354 was published on 2016-09-21 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:a:westes:flex:*:*:*:*:*:*:*:*

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