CVE-2016-6354

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-17. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 9%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
52(Track)
EG Risk 52/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation9% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
94.6%
KEV
Not listed

Published

September 21, 2016

Last Modified

May 6, 2026

Advisory Details (5)

Auto-updated May 9, 2026
No patch confirmed yet.
generic

flex: Potential insecure code generation (GLSA 201701-31) — Gentoo security

https://security.gentoo.org/glsa/201701-31
generic

Fixed incorrect integer type · westes/flex@a5cbe92 · GitHub

https://github.com/westes/flex/commit/a5cbe929ac3255d371e698f62dc256afe7006466
generic

oss-security - Re: CVE request: flex: Buffer overflow in generated code (yy_get_next_buffer)

http://www.openwall.com/lists/oss-security/2016/07/26/12
generic

oss-security - CVE request: flex: Buffer overflow in generated code (yy_get_next_buffer)

http://www.openwall.com/lists/oss-security/2016/07/18/8
generic

[SECURITY] [DSA 3653-1] flex security update

http://www.debian.org/security/2016/dsa-3653

Data Freshness Timeline

(refreshed 12× in last 7d / 38× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 102 total refreshes for this CVE.

  1. 2026-07-24 14:13 UTCEPSS rescore
  2. 2026-07-23 14:15 UTCEPSS rescore
  3. 2026-07-23 01:23 UTCEG score recompute
  4. 2026-07-22 22:03 UTCEG score recompute
  5. 2026-07-22 14:04 UTCEPSS rescore
  6. 2026-07-21 15:21 UTCEPSS rescore
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  8. 2026-07-20 17:04 UTCEPSS rescore
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  13. 2026-07-18 10:00 UTCEPSS rescore
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  15. 2026-07-16 16:59 UTCEPSS rescore
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  17. 2026-07-15 16:54 UTCEPSS rescore
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  20. 2026-07-13 22:26 UTCEPSS rescore
  21. 2026-07-12 05:43 UTCEPSS rescore
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  23. 2026-07-11 08:24 UTCEPSS rescore
  24. 2026-07-09 19:06 UTCEPSS rescore
  25. 2026-07-08 08:35 UTCOSV refresh
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  1. 2026-07-07 13:42 UTCEPSS rescore
  2. 2026-07-06 02:20 UTCEPSS rescore
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  4. 2026-07-05 02:27 UTCEPSS rescore
  5. 2026-07-04 06:28 UTCEPSS rescore
  6. 2026-07-01 15:02 UTCEPSS rescore
  7. 2026-06-30 23:19 UTCEPSS rescore
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  9. 2026-06-29 14:03 UTCEPSS rescore
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  11. 2026-06-28 04:53 UTCEPSS rescore
  12. 2026-06-27 03:05 UTCEPSS rescore
  13. 2026-06-25 13:47 UTCEPSS rescore
  14. 2026-06-24 14:02 UTCEPSS rescore
  15. 2026-06-23 21:30 UTCEPSS rescore
  16. 2026-06-22 14:23 UTCEPSS rescore
  17. 2026-06-21 14:54 UTCEPSS rescore
  18. 2026-06-21 14:54 UTCEPSS rescore
  19. 2026-06-21 01:57 UTCEPSS rescore
  20. 2026-06-21 01:57 UTCEPSS rescore
  21. 2026-06-19 20:23 UTCOSV refresh
  22. 2026-06-19 19:23 UTCEPSS rescore
  23. 2026-06-19 19:23 UTCEPSS rescore
  24. 2026-06-18 17:50 UTCEPSS rescore
  25. 2026-06-18 17:50 UTCEPSS rescore
  26. 2026-06-17 17:50 UTCEPSS rescore
  27. 2026-06-17 17:50 UTCEPSS rescore
  28. 2026-06-16 17:50 UTCEPSS rescore
  29. 2026-06-15 17:45 UTCEPSS rescore
  30. 2026-06-14 23:14 UTCEPSS rescore
  31. 2026-06-14 23:14 UTCEPSS rescore
  32. 2026-06-13 22:57 UTCEPSS rescore
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  34. 2026-06-12 23:09 UTCEPSS rescore
  35. 2026-06-11 13:57 UTCEPSS rescore
  36. 2026-06-07 15:22 UTCEPSS rescore
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  38. 2026-06-06 13:45 UTCEPSS rescore
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  40. 2026-06-05 22:44 UTCEPSS rescore
  41. 2026-06-05 06:08 UTCEPSS rescore
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  43. 2026-06-02 20:10 UTCEPSS rescore
  44. 2026-06-01 13:49 UTCEPSS rescore
  45. 2026-06-01 13:49 UTCEPSS rescore
  46. 2026-05-31 22:28 UTCEPSS rescore
  47. 2026-05-31 22:28 UTCEPSS rescore
  48. 2026-05-31 00:43 UTCOSV refresh
  49. 2026-05-31 00:14 UTCEPSS rescore
  50. 2026-05-29 13:41 UTCEPSS rescore
  51. 2026-05-28 13:42 UTCEPSS rescore
  52. 2026-05-28 13:42 UTCEPSS rescore
  53. 2026-05-27 13:38 UTCEPSS rescore
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  63. 2026-05-20 11:21 UTCEPSS rescore
  64. 2026-05-20 11:21 UTCEPSS rescore
  65. 2026-05-20 09:50 UTCGHSA enrichment
  66. 2026-05-20 05:42 UTCGHSA enrichment
  67. 2026-05-20 01:34 UTCGHSA enrichment
  68. 2026-05-19 21:26 UTCGHSA enrichment
  69. 2026-05-19 17:18 UTCGHSA enrichment
  70. 2026-05-19 13:10 UTCGHSA enrichment
  71. 2026-05-19 09:01 UTCGHSA enrichment
  72. 2026-05-19 04:53 UTCGHSA enrichment
  73. 2026-05-19 00:46 UTCEG score recompute
  74. 2026-05-19 00:46 UTCGHSA enrichment
  75. 2026-05-18 21:30 UTCEPSS rescore

Frequently asked(5)

What is CVE-2016-6354?
CVE-2016-6354 is a critical vulnerability published on September 21, 2016. Heap-based buffer overflow in the yygetnextbuffer 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 numto_read.
When was CVE-2016-6354 disclosed?
CVE-2016-6354 was first published in the National Vulnerability Database on September 21, 2016, with the most recent update on May 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-6354 actively exploited?
CVE-2016-6354 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 94.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2016-6354?
CVE-2016-6354 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2016-6354?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-6354, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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