Vulnerability-Lookup

GHSA-55WC-3PG8-JFW6

Vulnerability from github – Published: 2026-10-27 19:02 – Updated: 2026-10-27 19:02

Summary

undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor

Details

Impact

undici's decompress interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw. undici's engine converts a synchronous throw from a downstream handler into a per-request failure, but that protection is not in place when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, for example the built-in dump interceptor which throws when a response exceeds its maxSize, escapes as an uncaught exception and terminates the Node.js process.

A malicious or compromised HTTP server can crash any client that composes the decompress interceptor with dump (or another response handler that throws), by returning a small compressed body that decompresses to more than the configured limit. The compressed bytes on the wire are tiny, so only the decompressed size matters. If the application keeps the process alive with a global uncaught-exception handler, the affected request instead hangs until the body timeout.

Patches

Upgrade to undici 7.30.1 or 8.12.2.

Workarounds

Avoid composing the decompress interceptor with a response handler that throws during response processing (such as dump with a maxSize) until upgrading.

Severity

5.9 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "undici"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.15.0"
            },
            {
              "fixed": "7.30.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "undici"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "8.0.0"
            },
            {
              "fixed": "8.12.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-87029"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-248"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-27T19:02:10Z",
    "nvd_published_at": "2026-10-15T19:17:47Z",
    "severity": "MODERATE"
  },
  "details": "## Impact\n\nundici\u0027s `decompress` interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw. undici\u0027s engine converts a synchronous throw from a downstream handler into a per-request failure, but that protection is not in place when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, for example the built-in `dump` interceptor which throws when a response exceeds its `maxSize`, escapes as an uncaught exception and terminates the Node.js process.\n\nA malicious or compromised HTTP server can crash any client that composes the `decompress` interceptor with `dump` (or another response handler that throws), by returning a small compressed body that decompresses to more than the configured limit. The compressed bytes on the wire are tiny, so only the decompressed size matters. If the application keeps the process alive with a global uncaught-exception handler, the affected request instead hangs until the body timeout.\n\n## Patches\n\nUpgrade to undici 7.30.1 or 8.12.2.\n\n## Workarounds\n\nAvoid composing the `decompress` interceptor with a response handler that throws during response processing (such as `dump` with a `maxSize`) until upgrading.",
  "id": "GHSA-55wc-3pg8-jfw6",
  "modified": "2026-10-27T19:02:10Z",
  "published": "2026-10-27T19:02:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/security/advisories/GHSA-55wc-3pg8-jfw6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87029"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/commit/63cba7712ca012b2603c6aeeb4c72d8692332cd0"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/commit/f851f315db1f2acce0ea668f88d9d0fa61c8420c"
    },
    {
      "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/v7.30.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodejs/undici/releases/tag/v8.12.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor"
}

CVE-2026-87029 (GCVE-0-2026-87029)

Vulnerability from cvelistv5 – Published: 2026-10-15 18:48 – Updated: 2026-10-16 19:58

Title

undici vulnerable to Denial of Service via unhandled exception in the decompress interceptor

Summary

undici is an HTTP client library for Node.js. In versions 7.15.0 through 7.30.0 and 8.0.0 through 8.12.1, its decompress interceptor forwards decompressed response data to the downstream handler from zlib stream event callbacks without catching exceptions those callbacks may throw, and while undici's engine converts a synchronous throw from a downstream handler into a per-request failure, that protection is absent when the throw happens asynchronously from a zlib callback. As a result, a downstream handler that throws by design, such as the built-in dump interceptor which throws when a response exceeds its configured maximum size, escapes as an uncaught exception that terminates the Node.js process. A malicious or compromised HTTP server can crash any client that composes the decompress interceptor with such a handler by returning a small compressed body that decompresses to more than the configured limit, so only the decompressed size matters and the bytes on the wire stay tiny. The issue is fixed in undici 7.30.1 and 8.12.2, and users should upgrade to one of those versions or later. As a workaround, avoid composing the decompress interceptor with a response handler that throws during response processing until upgrading.

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-16 19:58 UTC

CWE

CWE-248 - Uncaught Exception

Assigner

openjs CNA under the redhat root

CNA scorecard C 65/100 over 121 records in the last 180 days details

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: 7.15.0 , < 7.30.1 (semver) Unaffected: 7.30.1 (semver) Affected: 8.0.0 , < 8.12.2 (semver) Unaffected: 8.12.2 (semver)

Credits

Yanhaoxi mcollina UlisesGascon

Show details on NVD website

JSON

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Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

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