Answer in brief
CVE-2026-18446 records a High severity ssrf vulnerability in fast-uri vulnerable to host confusion via backslash authority introducer. The source record does not mark it as known exploited. 3 affected packages are mapped in the feed.
Answer in brief
CVE-2026-18446 records a High severity ssrf vulnerability in fast-uri vulnerable to host confusion via backslash authority introducer. The source record does not mark it as known exploited. 3 affected packages are mapped in the feed.
Update fast-uri to 2.4.4; fast-uri to 3.1.5; fast-uri to 4.1.2 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanSSRF describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-18446 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| fast-urinpm | <2.4.4 | 2.4.4 |
| fast-urinpm | >=3.0.0,<3.1.5 | 3.1.5 |
| fast-urinpm | >=4.0.0,<4.1.2 | 4.1.2 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-18446 records a High severity ssrf vulnerability in fast-uri vulnerable to host confusion via backslash authority introducer. The source record does not mark it as known exploited. 3 affected packages are mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for fast-uri, fast-uri, fast-uri.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate fast-uri to 2.4.4; fast-uri to 3.1.5; fast-uri to 4.1.2 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanSSRF describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-18446 as known exploited; continue to monitor the source for status changes. The feed includes package mappings that can be checked against lockfiles and deployed manifests.
| Package | Affected range | Fixed version |
|---|---|---|
| fast-urinpm | <2.4.4 | 2.4.4 |
| fast-urinpm | >=3.0.0,<3.1.5 | 3.1.5 |
| fast-urinpm | >=4.0.0,<4.1.2 | 4.1.2 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-18446 records a High severity ssrf vulnerability in fast-uri vulnerable to host confusion via backslash authority introducer. The source record does not mark it as known exploited. 3 affected packages are mapped in the feed.
The source record does not mark it as known exploited.
Check lockfiles and deployed manifests for fast-uri, fast-uri, fast-uri.
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard### Impact `fast-uri` v4.1.1 and earlier require a literal `//` to recognize a URI authority, so a reference that uses `\\`, `/\`, or `\/` as the authority introducer (in place of `//`, after an optional scheme) is parsed with no authority: the sequence and everything after it fold into the path. Node's native WHATWG `URL` (used by `fetch()`, `undici`, and Node's `http`/`https` clients) instead treats `\` as interchangeable with `/` for special schemes (`http`, `https`, `ws`, `wss`, `ftp`, `file`), so the two parsers extract different hosts from the same input. For example, `fast-uri` resolves `\\evil.com/path` against base `https://allowed.com/` to `https://allowed.com/%5C%5Cevil.com/path` (confined to the trusted host), while Node's WHATWG URL resolves the same reference to `https://evil.com/path`. Applications that use `fast-uri` to enforce host-based policy (allowlists, denylists, loopback/SSRF filtering, redirect validation, outbound proxy routing) before passing the same URL into Node's URL or `fetch()` consumers see a policy/use desync and can be steered to an unintended destination. ### Patches Upgrade to `fast-uri` v4.1.2, v3.1.5, v2.4.4. ### Workarounds None. Upgrade to the patched version.
### Impact `fast-uri` v4.1.1 and earlier require a literal `//` to recognize a URI authority, so a reference that uses `\\`, `/\`, or `\/` as the authority introducer (in place of `//`, after an optional scheme) is parsed with no authority: the sequence and everything after it fold into the path. Node's native WHATWG `URL` (used by `fetch()`, `undici`, and Node's `http`/`https` clients) instead treats `\` as interchangeable with `/` for special schemes (`http`, `https`, `ws`, `wss`, `ftp`, `file`), so the two parsers extract different hosts from the same input. For example, `fast-uri` resolves `\\evil.com/path` against base `https://allowed.com/` to `https://allowed.com/%5C%5Cevil.com/path` (confined to the trusted host), while Node's WHATWG URL resolves the same reference to `https://evil.com/path`. Applications that use `fast-uri` to enforce host-based policy (allowlists, denylists, loopback/SSRF filtering, redirect validation, outbound proxy routing) before passing the same URL into Node's URL or `fetch()` consumers see a policy/use desync and can be steered to an unintended destination. ### Patches Upgrade to `fast-uri` v4.1.2, v3.1.5, v2.4.4. ### Workarounds None. Upgrade to the patched version.