{"id":"CVE-2026-53505","aliases":["DEBIAN-CVE-2026-53505","EUVD-2026-51611","GHSA-phj3-59pf-cp83","PYSEC-2026-3621","UBUNTU-CVE-2026-53505"],"status":"published","title":"Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(\u003cvalue\u003e) filter does not enforce an upper bound on \u003cvalue\u003e and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00609,"percentile":0.49622,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400"],"published":"2026-07-31T19:00:22Z","modified":"2026-10-28T02:31:14Z","fixes":[{"ecosystem":"PyPI","package":"thumbor","fixed_in":["7.8.0"],"sources":["ghsa","osv"]},{"ecosystem":"Debian:14","package":"thumbor","fixed_in":["7.8.0-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"thumbor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"7.7.7"},{"fixed":"7.8.0"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"thumbor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.8.0-1"}]}],"versions":["6.3.2-3","6.3.2-4","6.5.1-1","6.5.1-2","6.5.1-3","6.5.1-4","6.5.1-5","6.5.1-6","6.5.1-7","6.7.0-1","7.7.7-1","7.7.7-2","7.7.7-3","7.7.7-4","7.7.7-5","7.7.7-6"]},{"source":"osv","ecosystem":"PyPI","package":"thumbor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.8.0"}]}],"versions":["4.1.3","4.10.0","4.10.1","4.10.2","4.10.3","4.11.0","4.11.1","4.12.0","4.12.1","4.12.2","4.4.1","4.5.3","4.5.4","4.6.0","4.7.0","4.7.1","4.8.0","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.9.0","4.9.1","5.0.0","5.0.0rc1","5.0.0rc2","5.0.1","5.0.2","5.0.3","5.0.4","5.0.5","5.0.6","5.1.0","5.2.0","5.2.1","6.0.0","6.0.0b1","6.0.0b2","6.0.0b3","6.0.0b4","6.0.0b5","6.0.1","6.0.2","6.1.0","6.1.1","6.1.2","6.1.3","6.1.4","6.1.5","6.2.0","6.2.1","6.3.0","6.3.1","6.3.2","6.4.0","6.4.1","6.4.2","6.4.3","6.5.0","6.5.1","6.5.2","6.6.0","6.6.1","6.7.0","6.7.1","6.7.2","6.7.3","6.7.4","6.7.5","6.7.6","7.0.0","7.0.0a1","7.0.0a2","7.0.0a3","7.0.0a4","7.0.0a5","7.0.0b1","7.0.1","7.0.10","7.0.11","7.0.12","7.0.2","7.0.3","7.0.5","7.0.6","7.0.7","7.0.8","7.0.9","7.1.0","7.1.1","7.1.2","7.2.0","7.2.1","7.3.0","7.3.1","7.3.2","7.4.0","7.4.1","7.4.2","7.4.3","7.4.4","7.4.5","7.4.6","7.4.7","7.5.0","7.5.1","7.5.2","7.6.0","7.7.0","7.7.1","7.7.2","7.7.3","7.7.4","7.7.5","7.7.6","7.7.7"]},{"source":"osv","ecosystem":"PyPI","package":"thumbor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.8.0"}]}],"versions":["4.1.3","4.10.0","4.10.1","4.10.2","4.10.3","4.11.0","4.11.1","4.12.0","4.12.1","4.12.2","4.4.1","4.5.3","4.5.4","4.6.0","4.7.0","4.7.1","4.8.0","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.9.0","4.9.1","5.0.0","5.0.0rc1","5.0.0rc2","5.0.1","5.0.2","5.0.3","5.0.4","5.0.5","5.0.6","5.1.0","5.2.0","5.2.1","6.0.0","6.0.0b1","6.0.0b2","6.0.0b3","6.0.0b4","6.0.0b5","6.0.1","6.0.2","6.1.0","6.1.1","6.1.2","6.1.3","6.1.4","6.1.5","6.2.0","6.2.1","6.3.0","6.3.1","6.3.2","6.4.0","6.4.1","6.4.2","6.4.3","6.5.0","6.5.1","6.5.2","6.6.0","6.6.1","6.7.0","6.7.1","6.7.2","6.7.3","6.7.4","6.7.5","6.7.6","7.0.0","7.0.0a1","7.0.0a2","7.0.0a3","7.0.0a4","7.0.0a5","7.0.0b1","7.0.1","7.0.10","7.0.11","7.0.12","7.0.2","7.0.3","7.0.5","7.0.6","7.0.7","7.0.8","7.0.9","7.1.0","7.1.1","7.1.2","7.2.0","7.2.1","7.3.0","7.3.1","7.3.2","7.4.0","7.4.1","7.4.2","7.4.3","7.4.4","7.4.5","7.4.6","7.4.7","7.5.0","7.5.1","7.5.2","7.6.0","7.7.0","7.7.1","7.7.2","7.7.3","7.7.4","7.7.5","7.7.6","7.7.7"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"thumbor","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.7.7-4","7.7.7-5"]}],"products":[{"vendor":"thumbor","product":"thumbor"}],"references":[{"url":"https://github.com/thumbor/thumbor/security/advisories/GHSA-phj3-59pf-cp83","tags":["x_refsource_CONFIRM","advisory","web","report"]},{"url":"https://github.com/thumbor/thumbor/commit/2c716119de986cfc68c7071af52a98187e006023","tags":["x_refsource_MISC","fix","web","report"]},{"url":"https://github.com/thumbor/thumbor/releases/tag/7.8.0","tags":["x_refsource_MISC","web","report"]},{"url":"https://github.com/advisories/GHSA-phj3-59pf-cp83","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53505.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53505","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-53505","tags":["advisory"]},{"url":"https://github.com/thumbor/thumbor","tags":["package"]},{"url":"https://pypi.org/project/thumbor","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-53505","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-53505","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-53505","title":"Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(\u003cvalue\u003e) filter does not enforce an upper bound on \u003cvalue\u003e and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.","status":"published","published":"2026-07-31T19:00:22.755Z","modified":"2026-08-03T17:20:37.186Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:19:59.761005Z"}],"euvd":[{"id":"EUVD-2026-51611","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(\u003cvalue\u003e) filter does not enforce an upper bound on \u003cvalue\u003e and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.","status":"published","published":"2026-07-31T19:00:22Z","modified":"2026-08-03T17:20:37Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T18:02:24.01774Z"}],"ghsa":[{"id":"GHSA-phj3-59pf-cp83","title":"Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS","description":"### Summary\nThumbor's `filters:proportion(\u003cvalue\u003e)` filter does not enforce an upper bound on `\u003cvalue\u003e` and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service.\n\n### Details\n- Filter implementation: `thumbor/filters/proportion.py`\n  - `value` is parsed as a float (`BaseFilter.DecimalNumber`) with no maximum.\n  - The filter computes `new_width = source_width * value` and `new_height = source_height * value` and then calls `engine.resize(new_width, new_height)`.\n- Execution phase: `proportion` runs in the default POST_TRANSFORM phase (after the main transform pipeline). This means it can effectively bypass request-level size clamping that happens earlier in the request lifecycle (e.g., `MAX_WIDTH`/`MAX_HEIGHT` applied to `req.width/req.height`).\n\nDocumentation states the `percentage` argument should be `0.0 to 1.0` (`docs/proportion.rst`), but the implementation does not enforce this constraint.\n\n### PoC\n#### Preconditions\n- The `proportion` filter is enabled (it is enabled by default via `BUILTIN_FILTERS`).\n- Either:\n  - `/unsafe/` URLs are allowed (`ALLOW_UNSAFE_URL=True`, common default in some deployments), OR\n  - `/unsafe/` is disabled, and the attacker has a valid signed URL (i.e., the attacker is an authorized user/partner, or otherwise can obtain signed URLs issued by a trusted signing service).\n\n#### Example request 1 (signed URL)\nThe following request was used to reproduce the issue and causes severe resource exhaustion:\n\n`http://\u003chost\u003e:\u003cport\u003e/\u003curl-sign\u003e/100x100/filters:proportion(10000)/example.jpg`\n\n#### Example request 2 (/unsafe/)\nIf `/unsafe/` is enabled:\n\n`http://\u003chost\u003e:\u003cport\u003e/unsafe/100x100/filters:proportion(10000)/example.jpg`\n\n### Impact\n- Remote Denial of Service via CPU and/or memory exhaustion (and potentially process crash / OOM kill).\n- Exploitability depends on deployment:\n  - If `/unsafe/` is enabled: unauthenticated remote DoS.\n  - If `/unsafe/` is disabled: the attacker needs a valid signed URL (i.e., the attacker can legitimately request signed URLs, or has access to signed URLs issued for other users/partners). If signed URLs are not exposed to untrusted parties, exploitability is reduced but the risk still applies to any party who can generate/use signed URLs.\n\n### Suggested remediation\n- Enforce a strict bound on the `proportion` parameter (e.g., `0.0 \u003c value \u003c= 1.0` as documented), or define a safe maximum based on intended semantics.","status":"published","published":"2026-07-31T19:00:44Z","modified":"2026-07-31T19:00:45Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:40:55.903445Z"}],"nvd":[{"id":"CVE-2026-53505","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(\u003cvalue\u003e) filter does not enforce an upper bound on \u003cvalue\u003e and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.","status":"published","published":"2026-07-31T19:17:10.123Z","modified":"2026-09-08T20:51:43.49Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:12:34.290716Z"}],"osv":[{"id":"CVE-2026-53505","title":"Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(\u003cvalue\u003e) filter does not enforce an upper bound on \u003cvalue\u003e and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.","status":"published","published":"2026-07-31T19:00:22.755Z","modified":"2026-10-28T02:31:14.926233948Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T15:45:08.132336Z"},{"id":"DEBIAN-CVE-2026-53505","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(\u003cvalue\u003e) filter does not enforce an upper bound on \u003cvalue\u003e and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.","status":"published","published":"2026-07-31T19:17:10.123Z","modified":"2026-10-01T03:03:18.894087442Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:45:57.236551Z"},{"id":"GHSA-phj3-59pf-cp83","title":"Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS","description":"### Summary\nThumbor's `filters:proportion(\u003cvalue\u003e)` filter does not enforce an upper bound on `\u003cvalue\u003e` and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service.\n\n### Details\n- Filter implementation: `thumbor/filters/proportion.py`\n  - `value` is parsed as a float (`BaseFilter.DecimalNumber`) with no maximum.\n  - The filter computes `new_width = source_width * value` and `new_height = source_height * value` and then calls `engine.resize(new_width, new_height)`.\n- Execution phase: `proportion` runs in the default POST_TRANSFORM phase (after the main transform pipeline). This means it can effectively bypass request-level size clamping that happens earlier in the request lifecycle (e.g., `MAX_WIDTH`/`MAX_HEIGHT` applied to `req.width/req.height`).\n\nDocumentation states the `percentage` argument should be `0.0 to 1.0` (`docs/proportion.rst`), but the implementation does not enforce this constraint.\n\n### PoC\n#### Preconditions\n- The `proportion` filter is enabled (it is enabled by default via `BUILTIN_FILTERS`).\n- Either:\n  - `/unsafe/` URLs are allowed (`ALLOW_UNSAFE_URL=True`, common default in some deployments), OR\n  - `/unsafe/` is disabled, and the attacker has a valid signed URL (i.e., the attacker is an authorized user/partner, or otherwise can obtain signed URLs issued by a trusted signing service).\n\n#### Example request 1 (signed URL)\nThe following request was used to reproduce the issue and causes severe resource exhaustion:\n\n`http://\u003chost\u003e:\u003cport\u003e/\u003curl-sign\u003e/100x100/filters:proportion(10000)/example.jpg`\n\n#### Example request 2 (/unsafe/)\nIf `/unsafe/` is enabled:\n\n`http://\u003chost\u003e:\u003cport\u003e/unsafe/100x100/filters:proportion(10000)/example.jpg`\n\n### Impact\n- Remote Denial of Service via CPU and/or memory exhaustion (and potentially process crash / OOM kill).\n- Exploitability depends on deployment:\n  - If `/unsafe/` is enabled: unauthenticated remote DoS.\n  - If `/unsafe/` is disabled: the attacker needs a valid signed URL (i.e., the attacker can legitimately request signed URLs, or has access to signed URLs issued for other users/partners). If signed URLs are not exposed to untrusted parties, exploitability is reduced but the risk still applies to any party who can generate/use signed URLs.\n\n### Suggested remediation\n- Enforce a strict bound on the `proportion` parameter (e.g., `0.0 \u003c value \u003c= 1.0` as documented), or define a safe maximum based on intended semantics.","status":"published","published":"2026-07-31T19:00:44Z","modified":"2026-08-04T14:41:08.686193516Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T15:46:53.244788Z"},{"id":"PYSEC-2026-3621","title":"Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS","description":"### Summary\nThumbor's `filters:proportion(\u003cvalue\u003e)` filter does not enforce an upper bound on `\u003cvalue\u003e` and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service.\n\n### Details\n- Filter implementation: `thumbor/filters/proportion.py`\n  - `value` is parsed as a float (`BaseFilter.DecimalNumber`) with no maximum.\n  - The filter computes `new_width = source_width * value` and `new_height = source_height * value` and then calls `engine.resize(new_width, new_height)`.\n- Execution phase: `proportion` runs in the default POST_TRANSFORM phase (after the main transform pipeline). This means it can effectively bypass request-level size clamping that happens earlier in the request lifecycle (e.g., `MAX_WIDTH`/`MAX_HEIGHT` applied to `req.width/req.height`).\n\nDocumentation states the `percentage` argument should be `0.0 to 1.0` (`docs/proportion.rst`), but the implementation does not enforce this constraint.\n\n### PoC\n#### Preconditions\n- The `proportion` filter is enabled (it is enabled by default via `BUILTIN_FILTERS`).\n- Either:\n  - `/unsafe/` URLs are allowed (`ALLOW_UNSAFE_URL=True`, common default in some deployments), OR\n  - `/unsafe/` is disabled, and the attacker has a valid signed URL (i.e., the attacker is an authorized user/partner, or otherwise can obtain signed URLs issued by a trusted signing service).\n\n#### Example request 1 (signed URL)\nThe following request was used to reproduce the issue and causes severe resource exhaustion:\n\n`http://\u003chost\u003e:\u003cport\u003e/\u003curl-sign\u003e/100x100/filters:proportion(10000)/example.jpg`\n\n#### Example request 2 (/unsafe/)\nIf `/unsafe/` is enabled:\n\n`http://\u003chost\u003e:\u003cport\u003e/unsafe/100x100/filters:proportion(10000)/example.jpg`\n\n### Impact\n- Remote Denial of Service via CPU and/or memory exhaustion (and potentially process crash / OOM kill).\n- Exploitability depends on deployment:\n  - If `/unsafe/` is enabled: unauthenticated remote DoS.\n  - If `/unsafe/` is disabled: the attacker needs a valid signed URL (i.e., the attacker can legitimately request signed URLs, or has access to signed URLs issued for other users/partners). If signed URLs are not exposed to untrusted parties, exploitability is reduced but the risk still applies to any party who can generate/use signed URLs.\n\n### Suggested remediation\n- Enforce a strict bound on the `proportion` parameter (e.g., `0.0 \u003c value \u003c= 1.0` as documented), or define a safe maximum based on intended semantics.","status":"published","published":"2026-08-04T11:34:46.455208Z","modified":"2026-08-04T14:30:19.307836566Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T15:52:56.847083Z"},{"id":"UBUNTU-CVE-2026-53505","description":"Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor's filters:proportion(\u003cvalue\u003e) filter does not enforce an upper bound on \u003cvalue\u003e and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service. This issue is fixed in 7.8.0.","status":"published","published":"2026-07-31T19:17:00Z","modified":"2026-08-06T00:20:53Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T16:56:41.382716Z"}]}}