SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-100837

Config.registryFor strips a single trailing dot and then uses strings.HasSuffix(hostname, fqdn) without requiring a DNS label boundary, so a registry entry such as [registries."ghcr.io."] is also applied to any host whose name merely ends in that byte…

MEDIUM 6.3EPSS 0.21%

Does this matter?

Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.

Description

Contrast (Edgeless Systems) through 1.20.0 performs unanchored suffix matching when selecting per-registry configuration in the imagepuller. Config.registryFor strips a single trailing dot and then uses strings.HasSuffix(hostname, fqdn) without requiring a DNS label boundary, so a registry entry such as [registries."ghcr.io."] is also applied to any host whose name merely ends in that byte sequence, including attacker-registered domains such as evilghcr.io. When an image or layer is pulled from such a sibling domain, the imagepuller sends the configured Authorization header (basic auth, registry token, or identity token), trusts the configured custom CA bundle, follows the configured mirror, and honours insecure-skip-verify (disabling TLS verification) for that host. Image integrity is not affected, as image bytes remain pinned by digest in the policy and are validated after the pull. Configurations that use a leading dot (e.g., [registries.".example.registry"]) are unaffected.

CVSS 4.0
6.3 MEDIUMCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/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/M
EPSS
0.21% probability · 11th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-1289
Source
disclosure@vulncheck.com
EPSS trend
0%3%5%27 September 2026: 0.21%26 October 2026: 0.21%27 September 202626 October 2026

EPSS moved from 0.2% on 27 September 2026 to 0.2% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.