https://db.gcve.eu Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Thu, 01 Oct 2026 01:38:39 +0000 https://db.gcve.eu/vuln/cve-2026-53505 <p><strong>Affected:</strong> thumbor</p> <p>Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor&#39;s filters:proportion(&lt;value&gt;) filter does not enforce an upper bound on &lt;value&gt; 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.</p> <p><strong>Affected:</strong> thumbor</p> <p>Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, Thumbor&#39;s filters:proportion(&lt;value&gt;) filter does not enforce an upper bound on &lt;value&gt; 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.</p> https://db.gcve.eu/vuln/cve-2026-53505 https://db.gcve.eu/vuln/pysec-2026-3621 <p><strong>Affected:</strong> PyPI: thumbor</p> <p>### Summary Thumbor&#39;s `filters:proportion(&lt;value&gt;)` filter does not enforce an upper bound on `&lt;value&gt;` and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service.</p> <p>### Details - Filter implementation: `thumbor/filters/proportion.py` - `value` is parsed as a float (`BaseFilter.DecimalNumber`) with no maximum. - The filter computes `new_width = source_width * value` and `new_height = source_height * value` and then calls `engine.resize(new_width, new_height)`. - 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`).</p> <p>Documentation states the `percentage` argument should be `0.0 to 1.0` (`docs/proportion.rst`), but the implementation does not enforce this constraint.</p> <p>### PoC #### Preconditions - The `proportion` filter is enabled (it is enabled by default via `BUILTIN_FILTERS`). - Either: - `/unsafe/` URLs are allowed (`ALLOW_UNSAFE_URL=True`, common default in some deployments), OR - `/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).</p> <p>#### Example request 1 (signed URL) The following request was used to reproduce the issue and…</p> <p><strong>Affected:</strong> PyPI: thumbor</p> <p>### Summary Thumbor&#39;s `filters:proportion(&lt;value&gt;)` filter does not enforce an upper bound on `&lt;value&gt;` and runs in the post-transform phase. An attacker can trigger extremely large resizes (CPU/memory exhaustion) and cause denial of service.</p> <p>### Details - Filter implementation: `thumbor/filters/proportion.py` - `value` is parsed as a float (`BaseFilter.DecimalNumber`) with no maximum. - The filter computes `new_width = source_width * value` and `new_height = source_height * value` and then calls `engine.resize(new_width, new_height)`. - 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`).</p> <p>Documentation states the `percentage` argument should be `0.0 to 1.0` (`docs/proportion.rst`), but the implementation does not enforce this constraint.</p> <p>### PoC #### Preconditions - The `proportion` filter is enabled (it is enabled by default via `BUILTIN_FILTERS`). - Either: - `/unsafe/` URLs are allowed (`ALLOW_UNSAFE_URL=True`, common default in some deployments), OR - `/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).</p> <p>#### Example request 1 (signed URL) The following request was used to reproduce the issue and…</p> https://db.gcve.eu/vuln/pysec-2026-3621