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6 vulnerabilities found for py7zr by miurahr
CVE-2026-55206 (GCVE-0-2026-55206)
Vulnerability from nvd – Published: 2026-07-08 20:32 – Updated: 2026-07-09 14:26
VLAI
EPSS
VEX
Title
py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()
Summary
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, PackInfo._read() in archiveinfo.py used an O(n^2) cumulative sum pattern for attacker-controlled numstreams values parsed from archive headers, allowing a crafted .7z archive to cause excessive CPU consumption during SevenZipFile.init() before extraction. This issue is fixed in version 1.1.3.
Severity
SSVC
Exploitation: poc
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/miurahr/py7zr/security/advisor… | x_refsource_CONFIRM |
| https://github.com/miurahr/py7zr/commit/d7aa3a197… | x_refsource_MISC |
| https://github.com/miurahr/py7zr/releases/tag/v1.1.3 | x_refsource_MISC |
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CVE-2026-55195 (GCVE-0-2026-55195)
Vulnerability from nvd – Published: 2026-07-08 20:30 – Updated: 2026-07-09 14:06
VLAI
EPSS
VEX
Title
py7zr: Decompression bomb (zip bomb) denial of service via unchecked extraction size
Summary
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, py7zr's Worker.decompress() extracted archive entries without tracking total decompressed size, allowing a crafted .7z file such as a 15.6 KB archive that expands to 100 MB to exhaust disk or memory before extraction completes. This issue is fixed in version 1.1.3.
Severity
SSVC
Exploitation: poc
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/miurahr/py7zr/security/advisor… | x_refsource_CONFIRM |
| https://github.com/miurahr/py7zr/commit/28faf107b… | x_refsource_MISC |
| https://github.com/miurahr/py7zr/releases/tag/v1.1.3 | x_refsource_MISC |
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CVE-2026-23879 (GCVE-0-2026-23879)
Vulnerability from nvd – Published: 2026-06-24 19:17 – Updated: 2026-06-25 15:57
VLAI
EPSS
VEX
Title
py7zr: Arbitrary File Write Vulnerability
Summary
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Versions 1.1.2 and below contain an an arbitrary file write vulnerability, which allows symbolic links to be recreated outside the destination directory via crafted malicious symbolic link chains. When using extractall to extract an archive, the library restores these symbolic links, linking them to arbitrary directories on the host file system. During extraction, the program only checks the link arcname within the destination directory, but ignores the combined symlink path resolution. Attackers can exploit this vulnerability by constructing malicious archives, thereby bypassing the directory boundary restrictions implemented by the extractor. Subsequent extraction of regular files through these symbolic links can result in arbitrary file writes. This vulnerability may lead to remote code execution, privilege escalation, data corruption, or denial of service. This issue has been fixed in version 1.1.3.
Severity
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/miurahr/py7zr/security/advisor… | x_refsource_CONFIRM |
| https://github.com/miurahr/py7zr/releases/tag/v1.1.3 | x_refsource_MISC |
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CVE-2026-55206 (GCVE-0-2026-55206)
Vulnerability from cvelistv5 – Published: 2026-07-08 20:32 – Updated: 2026-07-09 14:26
VLAI
EPSS
VEX
Title
py7zr: O(n^2) algorithmic complexity DoS in PackInfo._read()
Summary
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, PackInfo._read() in archiveinfo.py used an O(n^2) cumulative sum pattern for attacker-controlled numstreams values parsed from archive headers, allowing a crafted .7z archive to cause excessive CPU consumption during SevenZipFile.init() before extraction. This issue is fixed in version 1.1.3.
Severity
SSVC
Exploitation: poc
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/miurahr/py7zr/security/advisor… | x_refsource_CONFIRM |
| https://github.com/miurahr/py7zr/commit/d7aa3a197… | x_refsource_MISC |
| https://github.com/miurahr/py7zr/releases/tag/v1.1.3 | x_refsource_MISC |
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CVE-2026-55195 (GCVE-0-2026-55195)
Vulnerability from cvelistv5 – Published: 2026-07-08 20:30 – Updated: 2026-07-09 14:06
VLAI
EPSS
VEX
Title
py7zr: Decompression bomb (zip bomb) denial of service via unchecked extraction size
Summary
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Prior to 1.1.3, py7zr's Worker.decompress() extracted archive entries without tracking total decompressed size, allowing a crafted .7z file such as a 15.6 KB archive that expands to 100 MB to exhaust disk or memory before extraction completes. This issue is fixed in version 1.1.3.
Severity
SSVC
Exploitation: poc
Automatable: yes
Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
- CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/miurahr/py7zr/security/advisor… | x_refsource_CONFIRM |
| https://github.com/miurahr/py7zr/commit/28faf107b… | x_refsource_MISC |
| https://github.com/miurahr/py7zr/releases/tag/v1.1.3 | x_refsource_MISC |
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CVE-2026-23879 (GCVE-0-2026-23879)
Vulnerability from cvelistv5 – Published: 2026-06-24 19:17 – Updated: 2026-06-25 15:57
VLAI
EPSS
VEX
Title
py7zr: Arbitrary File Write Vulnerability
Summary
py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Versions 1.1.2 and below contain an an arbitrary file write vulnerability, which allows symbolic links to be recreated outside the destination directory via crafted malicious symbolic link chains. When using extractall to extract an archive, the library restores these symbolic links, linking them to arbitrary directories on the host file system. During extraction, the program only checks the link arcname within the destination directory, but ignores the combined symlink path resolution. Attackers can exploit this vulnerability by constructing malicious archives, thereby bypassing the directory boundary restrictions implemented by the extractor. Subsequent extraction of regular files through these symbolic links can result in arbitrary file writes. This vulnerability may lead to remote code execution, privilege escalation, data corruption, or denial of service. This issue has been fixed in version 1.1.3.
Severity
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
- CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/miurahr/py7zr/security/advisor… | x_refsource_CONFIRM |
| https://github.com/miurahr/py7zr/releases/tag/v1.1.3 | x_refsource_MISC |
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