{"items":[{"id":"NVI-00015090","kind":"vulnerability","title":"Thumbor convolution filter allows divide-by-zero in C extension leading to remote DoS","revision":2,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-cqjp-jf4r-h5q9","CVE-2026-53503"],"plain_summary":"GitHub lists this reviewed advisory for thumbor. 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-29e2508bcfa3bb72862a38165934d019"],"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":"2026-07-31T18:54:57.000Z","value":"7.5 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-1e4d3ce37a6e74f83a1cd90e7ea6e997"},{"kind":"EPSS","as_of":"2026-11-03T12:00:27.000Z","value":"0.750%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.55021. Missing scores are unknown.","source_id":"sr-29e2508bcfa3bb72862a38165934d019"}],"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-1e4d3ce37a6e74f83a1cd90e7ea6e997","url":"https://github.com/advisories/GHSA-cqjp-jf4r-h5q9","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-cqjp-jf4r-h5q9","publisher":"GitHub Advisory Database","observed_at":"2026-11-03T09:58:33.950Z"},{"id":"sr-29e2508bcfa3bb72862a38165934d019","url":"https://www.first.org/epss/data.html","basis":"official_catalog","notes":"FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.","title":"CVE-2026-53503","publisher":"FIRST EPSS","observed_at":"2026-11-03T17:44:07.787Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-1e4d3ce37a6e74f83a1cd90e7ea6e997"],"technology":"thumbor","known_exclusions":[],"conditions_summary":"### Summary\nThumbor's `filters:convolution(, , )` filter passes the user-controlled `` value to a C extension (`thumbor/ext/filters/_convolution.c`) where it is used as a divisor (for `%` and `/`) without validating `columns > 0`. When `columns=0`, the C code triggers undefined behavior; on x86_64 this reliably results in a fatal divide-by-zero trap (SIGFPE) and crashes the Thumbor process (confirmed on Linux x86_64 and macOS Intel x86_64), causing a remote denial of service.\n\n### Details\n#### Root cause\nThe Python filter accepts `columns=0`, and the native C extension uses `columns_count` as a divisor without validating it.\n\n1) Python filter entry point allows `columns=0` (`thumbor/filters/convolution.py`):\n```python\n@filter_method(\n    r\"(?:[-]?[\\d]+\\.?[\\d]*[;])*(?:[-]?[\\d]+\\.?[\\d]*)\",\n    BaseFilter.PositiveNumber,  # accepts 0\n    BaseFilter.Boolean,\n)\nasync def convolution(self, matrix, columns, should_normalize=True):\n    ...\n    imgdata = _convolution.apply(..., matrix, columns, should_normalize)\n```\n`BaseFilter.PositiveNumber` matches `\"0\"` (`thumbor/filters/__init__.py`):\n```python\nclass BaseFilter:\n    PositiveNumber = {\"regex\":","public_affected_ranges":["<= 7.7.7"]}],"null_published_at":"2026-11-08T19:53:33.626Z","source_updated_at":"2026-07-31T18:54:57.000Z","source_disclosed_at":"2026-07-31T18:54:55.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.","null_first_observed_at":"2026-11-03T09:58:33.950Z"},{"id":"NVI-00015090","kind":"vulnerability","title":"Thumbor convolution filter allows divide-by-zero in C extension leading to remote DoS","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-cqjp-jf4r-h5q9","CVE-2026-53503"],"plain_summary":"GitHub lists this reviewed advisory for thumbor. 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-1e4d3ce37a6e74f83a1cd90e7ea6e997"],"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":"2026-07-31T18:54:57.000Z","value":"7.5 high","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-1e4d3ce37a6e74f83a1cd90e7ea6e997"}],"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-1e4d3ce37a6e74f83a1cd90e7ea6e997","url":"https://github.com/advisories/GHSA-cqjp-jf4r-h5q9","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-cqjp-jf4r-h5q9","publisher":"GitHub Advisory Database","observed_at":"2026-11-03T09:58:33.950Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-1e4d3ce37a6e74f83a1cd90e7ea6e997"],"technology":"thumbor","known_exclusions":[],"conditions_summary":"### Summary\nThumbor's `filters:convolution(, , )` filter passes the user-controlled `` value to a C extension (`thumbor/ext/filters/_convolution.c`) where it is used as a divisor (for `%` and `/`) without validating `columns > 0`. When `columns=0`, the C code triggers undefined behavior; on x86_64 this reliably results in a fatal divide-by-zero trap (SIGFPE) and crashes the Thumbor process (confirmed on Linux x86_64 and macOS Intel x86_64), causing a remote denial of service.\n\n### Details\n#### Root cause\nThe Python filter accepts `columns=0`, and the native C extension uses `columns_count` as a divisor without validating it.\n\n1) Python filter entry point allows `columns=0` (`thumbor/filters/convolution.py`):\n```python\n@filter_method(\n    r\"(?:[-]?[\\d]+\\.?[\\d]*[;])*(?:[-]?[\\d]+\\.?[\\d]*)\",\n    BaseFilter.PositiveNumber,  # accepts 0\n    BaseFilter.Boolean,\n)\nasync def convolution(self, matrix, columns, should_normalize=True):\n    ...\n    imgdata = _convolution.apply(..., matrix, columns, should_normalize)\n```\n`BaseFilter.PositiveNumber` matches `\"0\"` (`thumbor/filters/__init__.py`):\n```python\nclass BaseFilter:\n    PositiveNumber = {\"regex\":","public_affected_ranges":["<= 7.7.7"]}],"null_published_at":"2026-11-03T10:03:26.547Z","source_updated_at":"2026-07-31T18:54:57.000Z","source_disclosed_at":"2026-07-31T18:54:55.000Z","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":"2026-11-03T09:58:33.950Z"}],"next_cursor":null,"snapshot_revision":"42594"}