CVE-2016-6354

9.8 CRITICAL 9% exploit odds Fix listed Memory safety Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 9.1% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2016-09-21 14:25 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 00:50 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 9.1% in the next 30 days (EPSS).
Severity: 9.8 CRITICAL (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2016-09-21 14:25 UTC
Last modified: 2026-06-17 00:50 UTC
Exploit probability: 9.1% · EPSS, next 30 days
Weakness: CWE-119 · Buffer errors
Record status: Modified

Affected

Debian Linux 8.0
Westes Flex ≤ 2.6.0

Attack profile CVSS 3.0 · 9.8

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2016-6354.md and follow it. Check whether this project is affected by CVE-2016-6354. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record