CVE-2026-75975 (GCVE-0-2026-75975)

Vulnerability from cvelistv5 – Published: 2026-08-24 09:58 – Updated: 2026-08-24 14:30
VLAI
Title
fast-uri vulnerable to server-side request forgery via malformed IPv6 normalization
Summary
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-24 14:29 UTC
CWE
  • CWE-20 - Improper Input Validation
  • CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
openjs CNA under the redhat root
CNA scorecard C 65/100 over 99 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
fast-uri fast-uri Affected: 2.3.1 , < 2.4.5 (semver)
Unaffected: 2.4.5 (semver)
Affected: 3.0.0 , < 3.1.6 (semver)
Unaffected: 3.1.6 (semver)
Affected: 4.0.0 , < 4.1.3 (semver)
Unaffected: 4.1.3 (semver)
guessed Create a notification for this product.
Credits
mcollina UlisesGascon
Show details on NVD website
To clipboard 

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}



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Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.