HIGHCVSS v3.1 7.5Vulnerability
CVE-2026-126401
Fleet before 4.86.2 contains a denial of service vulnerability that allows unauthenticated attackers to exhaust server memory through quadratic XML canonicalization of unsigned SAML responses. Attackers can send a single crafted SAML response with deeply nested elements declaring new namespace prefixes to POST /api/v1/fleet/sso/callback, crashing the Fleet server.
Properties
- Severity
- HIGH
- Nvd fetched at
- 2026-11-14T00:40:25.638091+00:00
- Epss score
- 0.00509
- Cvss severity
- HIGH
- Cvss score
- 7.5
- Retrieved at
- 2026-11-14T00:51:03+00:00
- Last source
- FIRST EPSS
- Score
- 7.5
- Cvss version
- 3.1
- Cve id
- CVE-2026-126401
- Cvss vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- First seen by Signal
- 2026-11-13T17:31:47+00:00
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published at
- 2026-11-13T10:17:44.597
- Last modified
- 2026-11-13T10:17:44.597
- Epss percentile
- 0.44037
Related Entities (1)
HAS_WEAKNESS (1)
Related research
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