CVE-2026-39378Medium· 6.5▾ Sunlitnbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding
▾ Sunlit zone — Low / medium · no exploitation signal
impact 35.8 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 13.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
0.3%
Last analysed / modified upstream
When HTMLExporter.embed_images=True, nbconvert's markdown renderer allows arbitrary file read via path traversal in image references. A malicious notebook can exfiltrate sensitive files from the conversion host by embedding them as base64 data URIs in the output HTML.
Upgrade to nbconvert 7.17.1
Do not enable HTMLExporter.embed_images (it is not enabled by default).
nbconvert >= 6.5.0, < 7.17.1Upgrade to a patched release:
nbconvert 7.17.1Connected by shared product, vendor, weakness, or advisory.
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