{"items":[{"id":"NVI-00016123","kind":"vulnerability","title":"py7zr: Arbitrary File Write Vulnerability","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-q6rc-2cgv-63h7","CVE-2026-23879"],"plain_summary":"GitHub lists this reviewed advisory for py7zr. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-2819f59efc168acd8a1077835ffa9a6e"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-07-21T13:17:01.000Z","value":"8 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-2819f59efc168acd8a1077835ffa9a6e"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-2819f59efc168acd8a1077835ffa9a6e","url":"https://github.com/advisories/GHSA-q6rc-2cgv-63h7","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-q6rc-2cgv-63h7","publisher":"GitHub Advisory Database","observed_at":"2026-11-03T22:35:18.117Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-2819f59efc168acd8a1077835ffa9a6e"],"technology":"py7zr","known_exclusions":[],"conditions_summary":"### Summary\nThere exists an **arbitrary file write vulnerability** in `py7zr` (1.1.0, latest), 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. 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.\n\n### Details\nThe root cause of this vulnerability is that `py7zr` fails to properly restrict the targets of symbolic links within an archive. 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.\n\n\n\n\n### PoC\n#### **Construct PoC","public_affected_ranges":["<= 1.1.2"]}],"null_published_at":"2026-11-04T10:04:27.895Z","source_updated_at":"2026-07-21T13:17:01.000Z","source_disclosed_at":"2026-06-19T19:21:57.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-03T22:35:18.117Z"}],"next_cursor":null,"snapshot_revision":"42594"}