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No exploitation reportedFix available

CVE-2026-87029

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

No exploitation reported by the sources we read.

  • Published2026-10-15
  • Fixed in8.12.2 · 7.30.1
  • WeaknessCWE-248

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-10-1519:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-87029?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-87029?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Nodejs undici
BranchAffectedFixed in
8.x≥ 8.0.0, < 8.12.28.12.2
7.x≥ 7.15.0, < 7.30.17.30.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-87029 Red Hat Product Security56 products fixed · 113 known affected

    undici: undici: Denial of Service via unhandled exception in decompress interceptor

    cryostat/cryostat-openshift-console-plugin-rhel9 as a component of Cryostat 4 · exploit-intelligence/vulnerability-analysis-rhel9 as a component of Exploit Intelligence · amq-broker-bin.zip as a component of Red Hat AMQ Broker 7 · +110 more

  • RHSA-2026:84706 Red Hat Product Security28 products fixed

    Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

  • RHSA-2026:84657 Red Hat Product Security28 products fixed

    Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Full record on NVD

Fix

  1. Update Nodejs undici to 8.12.2 · 7.30.1
  2. Vendor fix Red Hat Product Security RHSA-2026:84706 · 28 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://images.redhat.com/
  3. No fix available, says the vendor Red Hat Product Security CVE-2026-87029 · 100 productsFix deferred
  4. No fix available, says the vendor Red Hat Product Security CVE-2026-87029 · 10 productsAffected
  5. No fix planned, says the vendor Red Hat Product Security CVE-2026-87029 · 2 productsOut of support scope
  6. No fix planned, says the vendor Red Hat Product Security CVE-2026-87029 · 1 productWill not fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2026-10-16
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.15.9read 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-248read 2026-10-23
  • FIRST EPSSEPSS score0.3 %2026-10-22

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-10-15
Last Modified
2026-10-19
NVD status
Analyzed

Frequently asked questions

What is CVE-2026-87029?

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.

Is CVE-2026-87029 actively exploited?

Active exploitation of CVE-2026-87029 has not been confirmed. Its EPSS score was 0.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-87029?

CVE-2026-87029 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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