CVE-2026-40036: Unfurl's unbounded zlib decompression allows decompression bomb DoS
(updated )
The compressed data parser uses zlib.decompress() without a maximum output size. A small, highly compressed payload can expand to a very large output, causing memory exhaustion and denial of service.
References
- github.com/RyanDFIR/unfurl/commit/7cc711a65b106742a21080b755f81c17b5725aa8
- github.com/RyanDFIR/unfurl/pull/243
- github.com/RyanDFIR/unfurl/releases/tag/v2026.04
- github.com/advisories/GHSA-h5qv-qjv4-pc5m
- github.com/obsidianforensics/unfurl
- github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m
- nvd.nist.gov/vuln/detail/CVE-2026-40036
- www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression
Code Behaviors & Features
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