CVE-2026-75975

Description

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.

CVSS Metrics

• v3.1•HIGH•Score: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Trends

Current EPSS score: 0.22%• Percentile: 13%

Techniques & Countermeasures

• CWE-20•Improper Input Validation

  The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

• CWE-918•Server-Side Request Forgery (SSRF)

  The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Affected Systems

• chainguard•airflow-2

  all

• chainguard•airflow-core-2

  all

• chainguard•arangodb-3.12

  all | < 3.12.11-r1

• chainguard•argo-workflows-ui-4.0

  < 4.0.11-r0

• chainguard•commercial-gitlab-rails-ee-19.1

  all

• chainguard•commercial-gitlab-rails-ee-19.2

  all

• chainguard•commercial-gitlab-rails-ee-19.3

  all

• chainguard•commercial-gitlab-rails-ee-fips-19.1

  all

• chainguard•commercial-gitlab-rails-ee-fips-19.2

  all

• chainguard•commercial-gitlab-rails-ee-fips-19.3

  all

• chainguard•gitlab-rails-ce-18.10

  all

• chainguard•gitlab-rails-ce-18.11

  all

• chainguard•gitlab-rails-ce-18.7

  all

• chainguard•gitlab-rails-ce-18.8

  all

• chainguard•gitlab-rails-ce-18.9

  all

• chainguard•gitlab-rails-ce-19.0

  all

• chainguard•gitlab-rails-ce-19.1

  < 19.1.7-r4

• chainguard•gitlab-rails-ce-19.3

  < 19.3.1-r6

• chainguard•gitlab-rails-ce-fips-18.10

  all

• chainguard•gitlab-rails-ce-fips-18.11

  all

• chainguard•gitlab-rails-ce-fips-18.7

  all

• chainguard•gitlab-rails-ce-fips-18.8

  all

• chainguard•gitlab-rails-ce-fips-18.9

  all

• chainguard•gitlab-rails-ce-fips-19.0

  all

• chainguard•gitlab-rails-ce-fips-19.1

  < 19.1.7-r5

• chainguard•jupyter-base-notebook

  all

• chainguard•keep-ui

  < 0.54.2-r8

• chainguard•keep-ui-fips

  < 0.54.2-r11

• chainguard•kibana-9.2

  < 9.2.8-r20

• chainguard•kibana-9.2-iamguarded

  < 9.2.8-r20

• chainguard•kibana-9.3

  all | < 9.3.8-r3

• chainguard•kibana-9.3-iamguarded

  all

• chainguard•langfuse-4

  < 4.27.0-r1

• chainguard•langfuse-4-worker

  < 4.27.0-r1

• chainguard•langfuse-fips-4

  < 4.26.0-r1

• chainguard•langfuse-fips-4-worker

  < 4.26.0-r1

• chainguard•nextcloud-server-32

  < 32.0.14-r1

• chainguard•nextcloud-server-34

  < 34.0.3-r3

• chainguard•opensearch-dashboards-2

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-alerting-dashboards-plugin

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-anomaly-detection-dashboards-plugin

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-dashboards-maps

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-dashboards-notifications

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-dashboards-observability

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-dashboards-query-workbench

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-dashboards-reporting

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-dashboards-search-relevance

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-dashboards-visualizations

  < 2.19.6-r16

• chainguard•opensearch-dashboards-2-fips

  < 2.19.6-r5

• chainguard•opensearch-dashboards-2-fips-alerting-dashboards-plugin

  < 2.19.6-r5

Showing first 50 affected entries in server-rendered view.

References (14)

• https://github.com/fastify/fast-uri/security/advisories/GHSA-f65p-4m7j-42xc
• https://cna.openjsf.org/security-advisories.html
• https://security-tracker.debian.org/tracker/CVE-2026-75975
• https://ubuntu.com/security/CVE-2026-75975
• https://www.cve.org/CVERecord?id=CVE-2026-75975
• https://nvd.nist.gov/vuln/detail/CVE-2026-75975
• https://github.com/fastify/fast-uri/commit/3728465caacef4b16bc84b7d14760f1c8fe41595
• https://github.com/fastify/fast-uri/commit/607bfbe953f28a14c2e06ae64aff38c81ca2937f
• https://github.com/fastify/fast-uri/commit/9161eded1ff55fad9d9714c6ad6c0f0283547799
• https://github.com/fastify/fast-uri
• https://github.com/fastify/fast-uri/releases/tag/v2.4.5
• https://github.com/fastify/fast-uri/releases/tag/v3.1.6
• https://github.com/fastify/fast-uri/releases/tag/v4.1.3
• https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75975.json