Vulnerability-Lookup

GHSA-2JFJ-6HJV-FM6J

Vulnerability from github – Published: 2026-09-29 18:19 – Updated: 2026-09-29 18:19

Summary

undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches

Details

Impact

undici's interceptors.cache() does not handle Set-Cookie in the cache path. In shared-cache mode (type: 'shared', the default), a cacheable response (for example Cache-Control: public, max-age=...) carrying a Set-Cookie header is stored, and the stored Set-Cookie is re-served to a later caller that hits the same cache key. This exposes one user's cookie to another caller and lets an untrusted upstream inject cookies into cached responses served to all subsequent callers, violating RFC 6265 section 7.2 (a shared cache must not store cookies). Applications using the shared cache interceptor against untrusted or multi-user upstreams are affected. Private caches (type: 'private') are not affected.

Patches

Upgrade to 7.29.1 or 8.10.2. In shared-cache mode, undici no longer stores or re-serves responses containing Set-Cookie, including previously cached entries and revalidation paths.

Workarounds

Use a private cache (type: 'private') for per-user responses, or avoid caching responses that set cookies. Applications acting as shared caches should strip Set-Cookie from responses before caching.

Severity

6.5 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "undici"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0"
            },
            {
              "fixed": "7.29.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "undici"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.10.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-84933"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-524"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-29T18:19:58Z",
    "nvd_published_at": "2026-09-04T17:17:01Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nundici\u0027s `interceptors.cache()` does not handle `Set-Cookie` in the cache path. In shared-cache mode (`type: \u0027shared\u0027`, the default), a cacheable response (for example `Cache-Control: public, max-age=...`) carrying a `Set-Cookie` header is stored, and the stored `Set-Cookie` is re-served to a later caller that hits the same cache key. This exposes one user\u0027s cookie to another caller and lets an untrusted upstream inject cookies into cached responses served to all subsequent callers, violating RFC 6265 section 7.2 (a shared cache must not store cookies). Applications using the shared cache interceptor against untrusted or multi-user upstreams are affected. Private caches (`type: \u0027private\u0027`) are not affected.\n\n### Patches\n\nUpgrade to `7.29.1` or `8.10.2`. In shared-cache mode, undici no longer stores or re-serves responses containing `Set-Cookie`, including previously cached entries and revalidation paths.\n\n### Workarounds\n\nUse a private cache (`type: \u0027private\u0027`) for per-user responses, or avoid caching responses that set cookies. Applications acting as shared caches should strip `Set-Cookie` from responses before caching.",
  "id": "GHSA-2jfj-6hjv-fm6j",
  "modified": "2026-09-29T18:19:58Z",
  "published": "2026-09-29T18:19:58Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/security/advisories/GHSA-2jfj-6hjv-fm6j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84933"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/commit/b6c5a00252c37da9dd2db9bead053bb843e1f988"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/commit/cb75bbb34224a968b4ad80cab8b7aba5e0b3b28a"
    },
    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nodejs/undici"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/releases/tag/v7.29.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/releases/tag/v8.10.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches"
}

CVE-2026-84933 (GCVE-0-2026-84933)

Vulnerability from cvelistv5 – Published: 2026-09-04 16:59 – Updated: 2026-09-04 18:34

Title

undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches

Summary

undici's cache interceptor does not handle the Set-Cookie response header anywhere in its cache path, so it neither refuses to store nor strips that header. In shared cache mode, which is the default, an otherwise cacheable response that carries a Set-Cookie header, for example one marked with a public and max-age directive, is stored and then re-served to a later caller that matches the same cache key. As a result one caller's cookie is disclosed to a different caller, and an untrusted server can inject cookies into cached responses served to all subsequent callers. This violates the requirement that a shared cache must not store cookies. This affects undici versions from 7.0.0 up to 7.29.1 and from 8.0.0 up to 8.10.2. Users should upgrade to undici 7.29.1 or 8.10.2.

Severity

6.5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-04 18:34 UTC

CWE

CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
CWE-524 - Use of Cache Containing Sensitive Information

Assigner

openjs redhat root Scorecard

References

2 references

URL	Tags
https://github.com/nodejs/undici/security/advisor…
https://cna.openjsf.org/security-advisories.html

Impacted products

1 product

Vendor	Product	Version
undici	undici	Affected: 7.0.0 , < 7.29.1 (semver) Unaffected: 7.29.1 (semver) Affected: 8.0.0 , < 8.10.2 (semver) Unaffected: 8.10.2 (semver)

Credits

mcollina UlisesGascon

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JSON

To clipboard

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      {
        "metrics": [
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                "id": "CVE-2026-84933",
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                  },
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                "role": "CISA Coordinator",
                "timestamp": "2026-09-04T18:34:06.167949Z",
                "version": "2.0.3"
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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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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