Skip to main content
No exploitation reportedFix available

CVE-2026-1526

No exploitation reported by the sources we read.

  • Published2026-03-12
  • Fixed in7.24.0 · 6.24.0
  • WeaknessCWE-409 · CWE-770

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

The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression. When a WebSocket connection negotiates the permessage-deflate extension, the client decompresses incoming compressed frames without enforcing any limit on the decompressed data size. A malicious WebSocket server can send a small compressed frame (a "decompression bomb") that expands to an extremely large size in memory, causing the Node.js process to exhaust available memory and crash or become unresponsive. The vulnerability exists in the PerMessageDeflate.decompress() method, which accumulates all decompressed chunks in memory and concatenates them into a single Buffer without checking whether the total size exceeds a safe threshold.

Timeline

dates in UTC
  1. 2026-03-1221:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 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-2026-1526?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-1526?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Nodejs undici
BranchAffectedFixed in
7.x≥ 7.0.0, < 7.24.07.24.0
6.24< 6.24.06.24.0

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.

Packages

  • nodejsAlmaLinux:9all versions · fixed in 1:24.14.1-2.module_el9.7.0+222+ef1c61e1and 4 other packages
  • nodejsAlmaLinux:8all versions · fixed in 1:22.22.2-1.module_el8.10.0+4158+e796f37fand 4 other packages
  • nodejsAlmaLinux:8all versions · fixed in 1:24.14.1-2.module_el8.10.0+4160+4819ac42and 4 other packages
  • nodejs-docsAlmaLinux:10all versions · fixed in 1:22.22.2-1.el10_1
  • nodejs-nodemonAlmaLinux:9all versions · fixed in 3.0.3-3.module_el9.7.0+209+ecf6523e
  • nodejs-nodemonAlmaLinux:8all versions · fixed in 3.0.1-1.module_el8.10.0+4006+3c416519
  • nodejs-nodemonAlmaLinux:8all versions · fixed in 3.0.3-1.module_el8.10.0+4061+f8ceeab9
  • nodejs-packagingAlmaLinux:9all versions · fixed in 2021.06-6.module_el9.7.0+209+ecf6523e

11 more package ranges on OSV.dev

Vendor advisories

  • RHSA-2026:56431 Red Hat Product Security68 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Data Foundation 4.18.27 security, enhancement & bug fix update

  • RHSA-2026:34342 Red Hat Product Security12 products fixed

    Red Hat Security Advisory: Cluster Observability Operator 1.5.0

  • RHSA-2026:21772 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat OpenShift Dev Spaces 3.28.0 Release.

  • RHSA-2026:17789 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat build of Cryostat 4.2.0: new RHEL 9 container image security update

  • RHSA-2026:13826 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Developer Hub 1.9.4 release.

  • RHSA-2026:9742 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Developer Hub 1.8.6 release.

9 more advisories

Full record on NVD

Fix

  1. Update Nodejs undici to 7.24.0 · 6.24.0
  2. Vendor fix Red Hat Product Security RHSA-2026:56431 · 68 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_openshift_data_foundation/4.18/html/updating_openshift_data_foundation/updating-ocs-…
  3. Vendor fix Red Hat Product Security RHSA-2026:34342 · 12 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2026:21772 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  5. Vendor fix Red Hat Product Security RHSA-2026:17789 · 4 productsYou can download the Cryostat 4 on RHEL 9 container images that this update provides from the Red Hat Container Registry at registry.access.redhat.com. Installation instructions for your platform are available in the Red Hat Container Catalog (see the References section). Dockerfiles and scripts s…
  6. Vendor fix Red Hat Product Security RHSA-2026:13826 · 1 productFor more about Red Hat Developer Hub, see References links
  7. Vendor fix Red Hat Product Security RHSA-2026:7983 · 43 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258

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

  • NVDCVE recordread 2026-10-23
  • CISA-ADPSSVC decisionnone2026-03-13
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.17.5read 2026-10-23
  • CNAweakness (CWE)CWE-409, CWE-770read 2026-10-23
  • FIRST EPSSEPSS score1.2 %2026-10-22
  • OSVaffected packages—

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
2026-03-12
Last Modified
2026-09-04
NVD status
Modified

Frequently asked questions

What is CVE-2026-1526?

The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression. When a WebSocket connection negotiates the permessage-deflate extension, the client decompresses incoming compressed frames without enforcing any limit on the decompressed data size. A malicious WebSocket server can send a small compressed frame (a "decompression bomb") that expands to an extremely large size in memory, causing the Node.js process to exhaust available memory and crash or become unresponsive. The vulnerability exists in the PerMessageDeflate.decompress() method, which accumulates all decompressed chunks in memory and concatenates them into a single Buffer without checking whether the total size exceeds a safe threshold.

Is CVE-2026-1526 actively exploited?

Active exploitation of CVE-2026-1526 has not been confirmed. Its EPSS score was 1.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-1526?

CVE-2026-1526 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.

Running undici? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this productCISA KEV additions, October 2026Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database