CVE Explorer

CVE-2026-55206

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.

Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:ab17e47f773c654ab1ce0f924848121ff8bc4c6d896e95275dcd6048405fa61c

Known exploited

Not asserted

Disputed

Stale source

Conflicts

Affected products and versions

1 source assertion

{"product":"py7zr","vendor":"miurahr","versions":[{"status":"affected","version":"< 1.1.3"}]}

cve_program_cvelist_v5affected
urn:baitaphish:normalized-source-record:v2:021a2c828aeafc837a48a7c53e65a00b8617ef8cb240972b1b9a5c36e7b949e7 · sha256:f84eadd47e51e877… · /containers/cna/affected/0

Provider-owned CVSS observations

1 source assertion

{"metric":{"attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.7,"baseSeverity":"HIGH","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE"},"metric_type":"cvssV4_0"}

cve_program_cvelist_v5cvss
urn:baitaphish:normalized-source-record:v2:021a2c828aeafc837a48a7c53e65a00b8617ef8cb240972b1b9a5c36e7b949e7 · sha256:f84eadd47e51e877… · /containers/cna/metrics/0/cvssV4_0

CWE assertions

1 source assertion

{"cweId":"CWE-407","description":"CWE-407: Inefficient Algorithmic Complexity","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:021a2c828aeafc837a48a7c53e65a00b8617ef8cb240972b1b9a5c36e7b949e7 · sha256:f84eadd47e51e877… · /containers/cna/problemTypes/0/descriptions/0

Source references

4 source assertions

{"name":"https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8","tags":["x_refsource_MISC"],"url":"https://github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:021a2c828aeafc837a48a7c53e65a00b8617ef8cb240972b1b9a5c36e7b949e7 · sha256:f84eadd47e51e877… · /containers/cna/references/1

{"name":"https://github.com/miurahr/py7zr/releases/tag/v1.1.3","tags":["x_refsource_MISC"],"url":"https://github.com/miurahr/py7zr/releases/tag/v1.1.3"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:021a2c828aeafc837a48a7c53e65a00b8617ef8cb240972b1b9a5c36e7b949e7 · sha256:f84eadd47e51e877… · /containers/cna/references/2

{"tags":["exploit"],"url":"https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:021a2c828aeafc837a48a7c53e65a00b8617ef8cb240972b1b9a5c36e7b949e7 · sha256:f84eadd47e51e877… · /containers/adp/0/references/0

{"name":"https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7","tags":["x_refsource_CONFIRM"],"url":"https://github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:021a2c828aeafc837a48a7c53e65a00b8617ef8cb240972b1b9a5c36e7b949e7 · sha256:f84eadd47e51e877… · /containers/cna/references/0

Attribution and limitations

CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →

Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.

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