CVE-2021-29921
CriticalPublic PoC
Published: 06 May 2021
Published
06 May 2021
Modified
03 November 2025
KEV Added
—
Patch
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CVSS Score v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score
0.0205
84.2th percentile
Risk Priority
21
60% EPSS · 20% KEV · 20% CVSS
Summary
CVE-2021-29921 is a critical-severity an unspecified weakness vulnerability in Python Python. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 15.8% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-16395
Vulnerability details
In Python before 3,9,5, the ipaddress library mishandles leading zero characters in the octets of an IP address string. This (in some situations) allows attackers to bypass access control that is based on IP addresses.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
python
python
3.8.0 — 3.8.12 · 3.9.0 — 3.9.5
oracle
communications cloud native core automated test suite
1.8.0
oracle
communications cloud native core binding support function
1.11.0
oracle
communications cloud native core network slice selection function
1.8.0
oracle
graalvm
20.3.2, 21.1.0
oracle
zfs storage appliance kit
8.8
Mitigating Controls
No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.