CVE-2016-5636

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-14. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 21%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

Integer overflow in the get_data function in zipimport.c in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 allows remote attackers to have unspecified impact via a negative data size value, which triggers a heap-based buffer overflow.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
65(Track*)
EG Risk 65/100SSVC: 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%
Exploitation40% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
97.3%
KEV
Not listed

Published

September 2, 2016

Last Modified

May 6, 2026

Advisory Details (7)

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

Issue 26171: heap overflow in zipimporter module - Python tracker

https://bugs.python.org/issue26171
generic🔴 Active Exploitation

SP-CAAAPUE | Splunk Vulnerability Disclosure

http://www.splunk.com/view/SP-CAAAPUE
generic🔴 Active Exploitation

SP-CAAAPSV | Splunk Vulnerability Disclosure

http://www.splunk.com/view/SP-CAAAPSV
generic
http://www.securityfocus.com/bid/91247
generic

oss-security - Re: CVE Request: heap overflow in Python zipimport module

http://www.openwall.com/lists/oss-security/2016/06/16/1
generic

oss-security - CVE Request: heap overflow in Python zipimport module

http://www.openwall.com/lists/oss-security/2016/06/15/15
generic
http://rhn.redhat.com/errata/RHSA-2016-2586.html

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntupython3.2-minimal (3.2.3-0ubuntu3.8) @ precise2026-05-20ubuntu
redhatpython-0:2.7.5-48.el72016-11-03redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 11× in last 7d / 36× 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 103 total refreshes for this CVE.

  1. 2026-07-23 14:14 UTCEPSS rescore
  2. 2026-07-23 01:23 UTCEG score recompute
  3. 2026-07-22 22:03 UTCEG score recompute
  4. 2026-07-22 14:04 UTCEPSS rescore
  5. 2026-07-21 15:21 UTCEPSS rescore
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  7. 2026-07-20 17:03 UTCEPSS rescore
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  16. 2026-07-13 22:26 UTCEPSS rescore
  17. 2026-07-13 06:09 UTCEPSS rescore
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  20. 2026-07-11 08:23 UTCEPSS rescore
  21. 2026-07-09 19:05 UTCEPSS rescore
  22. 2026-07-08 15:10 UTCEPSS rescore
  23. 2026-07-08 07:27 UTCOSV refresh
  24. 2026-07-06 16:24 UTCEPSS rescore
  25. 2026-07-06 16:24 UTCEPSS rescore
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  1. 2026-07-06 02:20 UTCEPSS rescore
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  3. 2026-07-04 06:28 UTCEPSS rescore
  4. 2026-07-01 15:02 UTCEPSS rescore
  5. 2026-06-30 23:19 UTCEPSS rescore
  6. 2026-06-28 14:04 UTCEPSS rescore
  7. 2026-06-28 04:53 UTCEPSS rescore
  8. 2026-06-27 03:05 UTCEPSS rescore
  9. 2026-06-27 03:05 UTCEPSS rescore
  10. 2026-06-25 13:47 UTCEPSS rescore
  11. 2026-06-25 13:47 UTCEPSS rescore
  12. 2026-06-24 14:02 UTCEPSS rescore
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  14. 2026-06-23 21:30 UTCEPSS rescore
  15. 2026-06-22 14:23 UTCEPSS rescore
  16. 2026-06-21 01:57 UTCEPSS rescore
  17. 2026-06-21 01:57 UTCEPSS rescore
  18. 2026-06-19 19:25 UTCOSV refresh
  19. 2026-06-18 17:50 UTCEPSS rescore
  20. 2026-06-17 17:50 UTCEPSS rescore
  21. 2026-06-17 17:50 UTCEPSS rescore
  22. 2026-06-16 17:50 UTCEPSS rescore
  23. 2026-06-16 17:50 UTCEPSS rescore
  24. 2026-06-15 17:45 UTCEPSS rescore
  25. 2026-06-12 23:09 UTCEPSS rescore
  26. 2026-06-12 23:09 UTCEPSS rescore
  27. 2026-06-11 13:57 UTCEPSS rescore
  28. 2026-06-10 22:15 UTCEPSS rescore
  29. 2026-06-10 13:18 UTCEPSS rescore
  30. 2026-06-08 14:14 UTCEPSS rescore
  31. 2026-06-06 13:45 UTCEPSS rescore
  32. 2026-06-05 22:44 UTCEPSS rescore
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  37. 2026-06-02 20:10 UTCEPSS rescore
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  40. 2026-05-31 22:28 UTCEPSS rescore
  41. 2026-05-31 22:28 UTCEPSS rescore
  42. 2026-05-31 00:14 UTCEPSS rescore
  43. 2026-05-31 00:13 UTCOSV refresh
  44. 2026-05-29 13:41 UTCEPSS rescore
  45. 2026-05-28 13:42 UTCEPSS rescore
  46. 2026-05-28 13:42 UTCEPSS rescore
  47. 2026-05-27 13:38 UTCEPSS rescore
  48. 2026-05-27 13:38 UTCEPSS rescore
  49. 2026-05-22 21:15 UTCEPSS rescore
  50. 2026-05-22 21:15 UTCEPSS rescore
  51. 2026-05-21 22:40 UTCEPSS rescore
  52. 2026-05-20 22:37 UTCEPSS rescore
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  55. 2026-05-20 11:21 UTCEPSS rescore
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  57. 2026-05-20 11:21 UTCEPSS rescore
  58. 2026-05-20 09:37 UTCVendor advisory
  59. 2026-05-20 09:37 UTCGHSA enrichment
  60. 2026-05-20 05:30 UTCVendor advisory
  61. 2026-05-20 05:30 UTCGHSA enrichment
  62. 2026-05-20 01:23 UTCVendor advisory
  63. 2026-05-20 01:23 UTCGHSA enrichment
  64. 2026-05-19 21:16 UTCVendor advisory
  65. 2026-05-19 21:16 UTCGHSA enrichment
  66. 2026-05-19 17:03 UTCVendor advisory
  67. 2026-05-19 17:03 UTCGHSA enrichment
  68. 2026-05-19 12:52 UTCVendor advisory
  69. 2026-05-19 12:52 UTCGHSA enrichment
  70. 2026-05-19 08:44 UTCVendor advisory
  71. 2026-05-19 08:44 UTCGHSA enrichment
  72. 2026-05-19 04:37 UTCVendor advisory
  73. 2026-05-19 04:37 UTCGHSA enrichment
  74. 2026-05-19 00:29 UTCEG score recompute
  75. 2026-05-19 00:29 UTCVendor advisory

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCinsuyun/CVE-2016-5636
    First seen Mar 28, 2016

    CVE-2016-5636

    Open source ↗

Frequently asked(5)

What is CVE-2016-5636?
CVE-2016-5636 is a critical vulnerability published on September 2, 2016. Integer overflow in the get_data function in zipimport.c in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 allows remote attackers to have unspecified impact via a negative data size value, which triggers a heap-based buffer overflow.
When was CVE-2016-5636 disclosed?
CVE-2016-5636 was first published in the National Vulnerability Database on September 2, 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-2016-5636 actively exploited?
CVE-2016-5636 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 97.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2016-5636?
CVE-2016-5636 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2016-5636?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-5636, 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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