CVE-2026-18446High· 7.5▾ TwilightA flaw was found in fast-uri. This vulnerability arises because fast-uri incorrectly parses Uniform Resource Identifiers (URIs) when a backslash is used in place of a forward slash to introduce the authority component. This discrepancy wit…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Aug 3.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CSAF
0.2%
Last analysed / modified upstream
0.2% → 0.4%
A flaw was found in fast-uri. This vulnerability arises because fast-uri incorrectly parses Uniform Resource Identifiers (URIs) when a backslash is used in place of a forward slash to introduce the authority component. This discrepancy with Node's native WHATWG URL parser can lead to host confusion. A remote attacker could exploit this to bypass security policies, such as allowlists or Server-Side Request Forgery (SSRF) filters, potentially redirecting applications to unintended hosts.
fast-uri: fast-uri: Host confusion vulnerability via backslash in URI authority — rated Important by Red Hat. Released 2026-07-31, updated 2026-10-23.
Affected:
Fixed:
No fix planned:
Not affected:
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/ https://access.redhat.com/errata/RHSA-2026:49401 For details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/ https://access.redhat.com/errata/RHSA-2026:49387 For Red Hat OpenShift AI 2.25.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update:
https://docs.redhat.com/en/documentation/red_hat_openshift_ai/ https://access.redhat.com/errata/RHSA-2026:87410
Workarounds / mitigations:
Affected packages:
fast-uri < 2.4.4fast-uri >= 3.0.0, < 3.1.5fast-uri >= 4.0.0, < 4.1.2Patched in:
fast-uri 2.4.4fast-uri 3.1.5fast-uri 4.1.2Connected by shared product, vendor, weakness, or advisory.
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