CVE-2026-84890

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 84% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — Patch released this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 0

A fix is available — apply it.

undici's decompress interceptor decompresses response bodies according to the untrusted Content-Encoding header. While the number of content-encoding layers is capped, the total decompressed output size is unbounded and there is no configuration option to limit it. A malicious or faulty upstream can therefore return a small compressed payload, a compression bomb, that expands to hundreds of megabytes or more in client memory, an asymmetric resource consumption that can exhaust memory and crash the process. This affects undici versions from 7.15.0 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.

CVSS v3
5.9
EG Score
5.9(medium)
EG Risk
27(Track)
EG Risk 27/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
16%
KEV
Not listed

Published

September 4, 2026

Last Modified

September 11, 2026

Advisory Details (2)

Auto-updated Sep 4, 2026
Patch available. Sources: github.
generic

Security Advisories | OpenJS Foundation CVE Numbering Authority

https://cna.openjsf.org/security-advisories.html
github Patch Available

undici vulnerable to Denial of Service via unbounded decompression of compressed responses · Advisory · nodejs/undici · GitHub

https://github.com/nodejs/undici/security/advisories/GHSA-3xpg-4rpp-hhhm

Vendor Advisories for CVE-2026-84890(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatgrafana12-4-main-12.4.10-0.2.hum12026-09-09redhat
redhatnodejs24-main-24.18.1-0.2.2.hum12026-08-12redhat
redhatnodejs26-main-26.7.0-1.5.2.hum12026-08-12redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
node-undici5.15.0+dfsg1+~cs20.10.9.3-1 ... 8.9.0+dfsg+~cs3.2.0-1 (39 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 8.9.0+dfsg+~cs3.2.0-1 (15 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
node-undici7.15.0+dfsg+~cs3.2.0-1 ... 8.9.0+dfsg+~cs3.2.0-1 (15 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 19× in last 7d / 23× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-11 17:12 UTCVendor advisory
  2. 2026-09-11 16:47 UTCEG score recompute
  3. 2026-09-11 16:47 UTCVendor advisory
  4. 2026-09-11 14:53 UTCEPSS rescore
  5. 2026-09-11 14:53 UTCEPSS rescore
  6. 2026-09-10 17:50 UTCEG score recompute
  7. 2026-09-10 17:50 UTCVendor advisory
  8. 2026-09-09 18:53 UTCEG score recompute
  9. 2026-09-09 18:53 UTCVendor advisory
  10. 2026-09-08 22:01 UTCEPSS rescore
  11. 2026-09-08 19:56 UTCVendor advisory
  12. 2026-09-08 16:19 UTCVendor advisory
  13. 2026-09-07 16:09 UTCEG score recompute
  14. 2026-09-07 16:09 UTCVendor advisory
  15. 2026-09-06 17:13 UTCEG score recompute
  16. 2026-09-06 17:13 UTCVendor advisory
  17. 2026-09-06 13:48 UTCEPSS rescore
  18. 2026-09-05 18:16 UTCEG score recompute
  19. 2026-09-05 15:31 UTCEPSS rescore
  20. 2026-09-04 19:19 UTCEG score recompute
  21. 2026-09-04 18:38 UTCEG score recompute
  22. 2026-09-04 17:20 UTCEG score recompute
  23. 2026-09-04 17:19 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-84890?
CVE-2026-84890 is a medium vulnerability published on September 4, 2026. undici's decompress interceptor decompresses response bodies according to the untrusted Content-Encoding header. While the number of content-encoding layers is capped, the total decompressed output size is unbounded and there is no configuration option to limit it. A malicious or faulty upstream…
When was CVE-2026-84890 disclosed?
CVE-2026-84890 was first published in the National Vulnerability Database on September 4, 2026, with the most recent update on September 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-84890 actively exploited?
CVE-2026-84890 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 83.6% of all scored CVEs.
What is the CVSS score of CVE-2026-84890?
CVE-2026-84890 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-84890?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-84890, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-84890

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