CVE-2026-80189 (CVSS 6.5)

Description

LeafWiki extracts an uploaded ZIP archive without limiting how much data it will write. ZipExtractor.ExtractToDir in internal/importer/zip_extractor.go opens each entry and copies it to the destination with io.Copy, which runs to the end of the decompressed stream, so only the size of the uploaded archive is bounded and the size it expands to is not. The import route that reaches this code requires the Editor or Admin role, and the upload itself is capped at 500 MiB compressed. Because a ZIP entry can compress at a very high ratio, an archive well inside that cap can expand to hundreds of gigabytes as it is written out. The extraction directory defaults to a location under the operating system temporary directory, so the written data consumes the disk backing that path, which on a tmpfs-backed temporary directory is memory. A user holding the Editor role can therefore exhaust the storage the service depends on and keep it from serving, using far more resource than the upload limit alone would permit.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0041

Probability of exploitation

0.35%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-409 CWE-409

References

Other References

https://github.com/perber/leafwiki https://github.com/perber/leafwiki/blob/v0.12.0/internal/importer/zip_extractor.go https://github.com/perber/leafwiki/releases/tag/v0.12.1 https://github.com/perber/leafwiki/security/advisories/GHSA-258m-crqp-25xc https://www.vulncheck.com/advisories/leafwiki-0.10.0-through-0.12.0-uncontrolled-resource-consumption-via-unbounded-zip-extraction

Frequently Asked Questions

What is CVE-2026-80189? +

LeafWiki extracts an uploaded ZIP archive without limiting how much data it will write. ZipExtractor.ExtractToDir in internal/importer/zip_extractor.go opens each entry and copies it to the destination with io.Copy, which runs to the end of the decompressed stream, so only the size of the uploaded archive is bounded and the size it expands to is not. The import route that reaches this code requires the Editor or Admin role, and the upload itself is capped at 500 MiB compressed. Because a ZIP entry can compress at a very high ratio, an archive well inside that cap can expand to hundreds of gigabytes as it is written out. The extraction directory defaults to a location under the operating system temporary directory, so the written data consumes the disk backing that path, which on a tmpfs-backed temporary directory is memory. A user holding the Editor role can therefore exhaust the storage the service depends on and keep it from serving, using far more resource than the upload limit alone would permit. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-80189? +

CVE-2026-80189 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0041, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-80189? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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