CVE-2026-53502— Thumbor has path traversal via post-validation URL decoding bypass in file_loader
Possible ATT&CK Techniques 1AI
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I. Basic Information for CVE-2026-53502
Vulnerability Information
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Vulnerability Title
Thumbor has path traversal via post-validation URL decoding bypass in file_loader
Source: CVE Program / CVE List V5
Vulnerability Description
Thumbor is an open-source photo thumbnail service by globo.com. Prior to 7.8.0, file_loader decodes percent-encoded path segments after its root-boundary validation, allowing traversal outside FILE_LOADER_ROOT_PATH through watermark or frame filter input. This issue is fixed in 7.8.0.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5
Vulnerability Title
thumbor 路径遍历漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
thumbor thumbor是thumbor组织开源的一个图像处理服务。 thumbor 7.8.0之前版本存在路径遍历漏洞，该漏洞源于file_loader在根边界验证后解码百分号编码的路径段，可通过watermark或frame filter输入进行路径遍历，导致访问FILE_LOADER_ROOT_PATH之外的文件。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-53502
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POCVerified env Premium
Qwen3.6-35B-A3B · 15733 chars
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III. Intelligence Information for CVE-2026-53502
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Patches & Fixes for CVE-2026-53502 (2)
- 🔗 Release Release 7.8.0 · thumbor/thumbor · GitHubx_refsource_MISC
Vendor Advisories for CVE-2026-53502 (1)
Same Patch Batch · thumbor · 2026-07-31 · 6 CVEs total
| CVE-2026-53500 | 8.2 HIGH | Thumbor treats ALLOWED_SOURCES string patterns as unescaped regex, allowing hostname bypas |
| CVE-2026-53501 | 8.2 HIGH | Thumbor has HMAC validation bypass via multiple .replace() calls when removing URL signatu |
| CVE-2026-53505 | 7.5 HIGH | Thumbor proportion filter allows unbounded post-transform resize leading to remote DoS |
| CVE-2026-53503 | 7.5 HIGH | Thumbor convolution filter allows divide-by-zero in C extension leading to remote DoS |
| CVE-2026-53504 | 7.5 HIGH | Thumbor has Regex Denial of Service (ReDoS) in `convolution` filter |
IV. Related Vulnerabilities
Same product: thumbor
- CVE-2026-53505
Thumbor proportion filter allows unbounded post-transform re - CVE-2026-53504
Thumbor has Regex Denial of Service (ReDoS) in `convolution` - CVE-2026-53503
Thumbor convolution filter allows divide-by-zero in C extens - CVE-2026-53501
Thumbor has HMAC validation bypass via multiple .replace() c - CVE-2026-53500
Thumbor treats ALLOWED_SOURCES string patterns as unescaped
Same vendor: thumbor
- CVE-2026-53505
Thumbor proportion filter allows unbounded post-transform re - CVE-2026-53504
Thumbor has Regex Denial of Service (ReDoS) in `convolution` - CVE-2026-53503
Thumbor convolution filter allows divide-by-zero in C extens - CVE-2026-53501
Thumbor has HMAC validation bypass via multiple .replace() c - CVE-2026-53500
Thumbor treats ALLOWED_SOURCES string patterns as unescaped
V. Comments for CVE-2026-53502
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