01 Record
CVE-2026-40036
Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression
HighPUBLISHEDCNA: VulnCheck
CNA base score8.7 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
02 Description
Unfurl < 2026.04 - Denial of Service via Unbounded zlib Decompression
03 Exploitation and scoring
- Exploitation
- Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
- SSVC decision
- ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.50% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 43.1% of scored records. A rank, not a probability.
- NVD base score
- 8.7 (CVSS v4.0), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVD analysis status
- Analyzed. NVD last modified this record on 2026-10-08.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-04-08 21:35Z6 MO AGO
- Last updated
- 2026-10-08 15:22Z21 DAYS AGO
- Reserved
- 2026-04-08
- Assigning CNA
- VulnCheck
- Record state
- PUBLISHED
- Severity
- High (CVSS 8.7)
- CNA CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Weaknesses
- Data version
- 5.2
- Document digest
- 4526342e04e49741868b90cc174f228210fa7d67b0468bf1db80d22c22b4696d
05 Affected products
VendorProductVersionsPlatforms
06 References
- github.comGHSA Advisory GHSA-h5qv-qjv4-pc5mhttps://github.com/obsidianforensics/unfurl/security/advisories/GHSA-h5qv-qjv4-pc5m
- github.comVulnCheck Advisory: dfir-unfurl - Denial of Service via Unbounded zlib Decompressionhttps://github.com/obsidianforensics/unfurl/releases/tag/v2026.04
- www.vulncheck.comhttps://www.vulncheck.com/advisories/dfir-unfurl-denial-of-service-via-unbounded-zlib-decompression