# Thumbor has path traversal via post-validation URL decoding bypass in file_loader Advisory record · `GHSA-cj54-hpcc-gj6h` - **Identifiers:** `GHSA-cj54-hpcc-gj6h` · `CVE-2026-53502` · `PYSEC-2026-3618` - **State:** Confirmed - **Severity:** CVSS 8.7 High - **Critical:** No - **Weakness (CWE):** [CWE-22](https://cwe.mitre.org/data/definitions/22.html) - **Tags:** [Path traversal](https://agentprime.io/advisories/tag/path-traversal.md) - **Published:** 31 Jul 2026 - **Updated:** 4 Aug 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 31 Jul 2026, 19:03 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `thumbor` (PyPI): affected `<7.8.0`; fixed in `7.8.0` ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Thumbor versions before 7.8.0 are affected by a path traversal flaw in the file loader. The loader decodes the file path after its security check, so percent-encoded parent-directory sequences pass the check and are then resolved by the operating system, letting an attacker read files outside the image root, for example through the watermark or frame filters when unsafe URLs are allowed (the default). Upgrade to Thumbor 7.8.0 or later; the source does not list a workaround other than that. Written 5 Nov 2026. ## Not analysed yet We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check. ## Severity and exploitation - 8.7 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N`, from CNA (GitHub_M) - **CISA KEV:** Not listed. - **EPSS:** 0.0052, the 44th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline - 31 Oct 2026, 14:41 UTC: First seen by agentprime - 31 Oct 2026, 14:41 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-cj54-hpcc-gj6h) ## Sources - [GitHub Advisory Database: GHSA-cj54-hpcc-gj6h](https://github.com/advisories/GHSA-cj54-hpcc-gj6h) - [OSV: GHSA-cj54-hpcc-gj6h](https://osv.dev/vulnerability/GHSA-cj54-hpcc-gj6h) - - - - Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code. ## Check whether this affects you A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet. - With the agentprime MCP server (), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .