How severe is CVE-2016-5636?

CVE-2016-5636 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-2016-5636 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 25% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-5636?

CVE-2016-5636 primarily affects Python. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-5636?

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-2016-5636 published?

CVE-2016-5636 was published on 2016-09-02 and last updated on 2026-06-17.

CVE-2016-5636

CVE-2016-5636 is a critical-severity vulnerability in Python with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 25% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-190.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 25% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Python
Published: 2016-09-02
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2016-5636?: 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.
How severe is CVE-2016-5636?: CVE-2016-5636 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-2016-5636 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 25% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-5636?: CVE-2016-5636 primarily affects Python. In total, 30 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-5636?: 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-2016-5636 published?: CVE-2016-5636 was published on 2016-09-02 and last updated on 2026-06-17.

References

Affected products (30)

cpe:2.3:a:python:python:3.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.0.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.1.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.1.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.1.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.1.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.1.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.1.5:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.2.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.2.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.2.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.2.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.2.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.2.5:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.2.6:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.3.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.3.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.3.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.3.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.3.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.3.5:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.3.6:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.4.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.4.1:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.4.2:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.4.3:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.4.4:*:*:*:*:*:*:*
cpe:2.3:a:python:python:*:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.5.0:*:*:*:*:*:*:*
cpe:2.3:a:python:python:3.5.1:*:*:*:*:*:*:*

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Other CWE-190 (Integer Overflow or Wraparound) vulnerabilities

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CVE-2015-5108 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2015-5097 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
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Threat intelligence

Threat-intel indicators referencing this CVE:

203.192.232.180 (ipv4-addr)
177.53.215.134 (ipv4-addr)
5.99.196.202 (ipv4-addr)
121.164.135.251 (ipv4-addr)