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Vulnerabilities

Vulnerability · CVE-2026-75975

fast-uri is a URI parser for Node.js.

Published Aug 24, 2026 · catalog updated Oct 15, 2026 · fast-uri is a URI

Check if you run it

No confirmed exploitation is on record for CVE-2026-75975. EPSS is 0.22%. Act only if a listed version of fast-uri is a URI is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (fast-uri is a URI).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.22%
Remediation
Advisory link
Affected products
Debian:13 node-ajv · Debian:14 node-ajv · cpe openjsf/fast-uri

fast-uri is a URI parser for Node.js. Its custom parser for bracketed IPv6 literals does not validate the complete IPv6 grammar, so invalid trailing text in an authority can be silently discarded and a malformed attacker-controlled host is turned into a different valid IPv6 destination. For example, a bracketed literal with invalid trailing characters is normalized to the unspecified address, which a Node HTTP client then connects to a local service over loopback, and other malformed literals collapse to private-range addresses. No error is set on the parsed result, so an application checking the error field cannot detect the rewrite. An application that normalizes untrusted URLs before outbound requests, redirects, proxy routing, or address-policy enforcement can be redirected to a local or private IPv6 target, giving a server-side request forgery and address-policy bypass primitive. The affected versions are 2.3.1 up to but not including 2.4.5, 3.0.0 up to but not including 3.1.6, and 4.0.0 up to but not including 4.1.3. The issue is fixed in 2.4.5, 3.1.6, and 4.1.3, which validate bracketed IP literals against the full grammar and mark malformed literals as authority errors. Users should upgrade to a patched version.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Debian:13 node-ajv8.12.0~ds+~2.1.1-5, 8.17.1~ds+~3.0.1+~3.1.0-1, 8.17.1~ds+~3.0.1+~3.1.0-2
  • Debian:14 node-ajv0 → 8.20.0~ds+~cs7.1.4-1
  • cpe openjsf/fast-uriversion unspecified

How to fix CVE-2026-75975

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-75975. EPSS is 0.22%. Act only if a listed version of fast-uri is a URI is installed.

Which versions are affected?

Compare what you have installed with 8.12.0~ds+~2.1.1-5, 8.17.1~ds+~3.0.1+~3.1.0-1, 8.17.1~ds+~3.0.1+~3.1.0-2, 0 → 8.20.0~ds+~cs7.1.4-1. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-20: Improper Input Validation; CWE-918: Server-Side Request Forgery (SSRF). EPSS 0.22%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Debian security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 24, 2026 · NIST NVD

    Detected

    fast-uri is a URI parser for Node.js. Its custom parser for bracketed IPv6 literals does not validate the complete IPv6 grammar, so invalid trailing text in an authority can be silently discarded and a malformed attacker-controlled host is turned into a different valid IPv6 destination. For example, a bracketed literal with invalid trailing characters is normalized to the unspecified address, whic

  2. Oct 14, 2026 · NIST NVD

    Updated

    fast-uri is a URI parser for Node.js. Its custom parser for bracketed IPv6 literals does not validate the complete IPv6 grammar, so invalid trailing text in an authority can be silently discarded and a malformed attacker-controlled host is turned into a different valid IPv6 destination. For example, a bracketed literal with invalid trailing characters is normalized to the unspecified address, whic

  3. Oct 15, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    node-ajv fixed in 8.20.0~ds+~cs7.1.4-1

  4. Oct 15, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    node-ajv fixed in 8.20.0~ds+~cs7.1.4-1

  5. Oct 15, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    fast-uri is a URI parser for Node.js. Its custom parser for bracketed IPv6 literals does not validate the complete IPv6 grammar, so invalid trailing text in an authority can be silently discarded and a malformed attacker-controlled host is turned into a different valid IPv6 destination. For example, a bracketed literal with invalid trailing characters is normalized to the unspecified address, whic

Sources

  • CVE.orgVulnerability recordCVE-2026-75975

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-75975

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-75975

    fast-uri is a URI parser for Node.js. Its custom parser for bracketed IPv6 literals does not validate the complete IPv6 grammar, so invalid trailing text in an authority can be silently discarded and a malformed attacker-controlled host is turned into a different valid IPv6 desti

    nvd.nist.gov
  • OpenSSF OSV / OSV ScannerPackage advisoryDEBIAN-CVE-2026-75975
    osv.dev

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.