Answer in brief
CVE-2026-13676 records a High severity (CVSS 7.5) security vulnerability in fast-uri vulnerable to host confusion via failed IDN canonicalization. The source record does not mark it as known exploited. 3 affected packages are mapped in the feed.
Answer in brief
CVE-2026-13676 records a High severity (CVSS 7.5) security vulnerability in fast-uri vulnerable to host confusion via failed IDN canonicalization. The source record does not mark it as known exploited. 3 affected packages are mapped in the feed.
Update fast-uri to 4.0.1; fast-uri to 3.1.3; fast-uri to 2.4.2 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanVulnerability describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-13676 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 | >=4.0.0,<4.0.1 | 4.0.1 |
| fast-urinpm | >=3.0.0,<3.1.3 | 3.1.3 |
| fast-urinpm | >=2.3.1,<2.4.2 | 2.4.2 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-13676 records a High severity (CVSS 7.5) security vulnerability in fast-uri vulnerable to host confusion via failed IDN canonicalization. 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 4.0.1; fast-uri to 3.1.3; fast-uri to 2.4.2 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanVulnerability describes the vulnerability class recorded for this advisory. The current record does not mark CVE-2026-13676 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 | >=4.0.0,<4.0.1 | 4.0.1 |
| fast-urinpm | >=3.0.0,<3.1.3 | 3.1.3 |
| fast-urinpm | >=2.3.1,<2.4.2 | 2.4.2 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
CVE-2026-13676 records a High severity (CVSS 7.5) security vulnerability in fast-uri vulnerable to host confusion via failed IDN canonicalization. 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` versions `>= 2.3.1, <= 4.0.0` fail to canonicalize Unicode/IDN hostnames for HTTP-family URLs. The IDN conversion path calls `URL.domainToASCII(...)` on the global WHATWG `URL` constructor, where that helper does not exist. The resulting `TypeError` is silently routed into `parsed.error`, but `parse()`, `normalize()`, and `equal()` all return with the host left in its original Unicode form. For example, `http://127。0。0。1/` is treated by `fast-uri` as host `127。0。0。1`, while Node's WHATWG URL parser and `fetch()` canonicalize the same input to `127.0.0.1`. Applications that use `fast-uri` to enforce host-based policy (denylists, loopback 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` v4.0.1, v3.1.3, or v2.4.2 ### Workarounds None. Upgrade to the patched version.
### Impact `fast-uri` versions `>= 2.3.1, <= 4.0.0` fail to canonicalize Unicode/IDN hostnames for HTTP-family URLs. The IDN conversion path calls `URL.domainToASCII(...)` on the global WHATWG `URL` constructor, where that helper does not exist. The resulting `TypeError` is silently routed into `parsed.error`, but `parse()`, `normalize()`, and `equal()` all return with the host left in its original Unicode form. For example, `http://127。0。0。1/` is treated by `fast-uri` as host `127。0。0。1`, while Node's WHATWG URL parser and `fetch()` canonicalize the same input to `127.0.0.1`. Applications that use `fast-uri` to enforce host-based policy (denylists, loopback 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` v4.0.1, v3.1.3, or v2.4.2 ### Workarounds None. Upgrade to the patched version.