GHSA-vrm6-8vpv-qv8q · Severity: high · Ecosystem: npm — Undici has Unbounded Memory Consumption in WebSocket permessage-deflate Decompression
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.
Conclusion & alert: CVE-2026-1526 is rated Low Risk (31.6/100): CVSS High severity, with low exploitation likelihood (EPSS 0.02%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-03-21 | 0.05% | 0.02% | -0.03% |
| 2 | 2026-03-17 | 0.04% | 0.05% | +0.01% |
| 3 | 2026-03-13 | — | 0.04% | — |
Full EPSS history (3 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | ce714d77-add3-4f53-aff5-83d477b104bb |
GHSA-vrm6-8vpv-qv8q · Severity: high · Ecosystem: npm — Undici has Unbounded Memory Consumption in WebSocket permessage-deflate Decompression
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2026-1526: 1 source package rows (nodejs); 10 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 10. | https://security.alpinelinux.org/vuln/CVE-2026-1526 |
debian
|
unimportant | CVE-2026-1526 unimportant priority: Debian including 1 source packages (node-undici), 4 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 3, open 1. | https://security-tracker.debian.org/tracker/CVE-2026-1526 |
redhat
|
high | — | https://access.redhat.com/security/cve/CVE-2026-1526 |
ubuntu
|
medium | CVE-2026-1526 medium priority: Ubuntu including 1 source packages (node-undici), 4 status rows across 4 suites (jammy, noble, questing, upstream): needs-triage 3, DNE 1. | https://ubuntu.com/security/CVE-2026-1526 |
| URL | Tags |
|---|---|
| https://cna.openjsf.org/security-advisories.html | Vendor Advisory |
| https://datatracker.ietf.org/doc/html/rfc7692 | Technical Description |
| https://github.com/nodejs/undici/security/advisories/GHSA-vrm6-8vpv-qv8q | Vendor Advisory |
| https://hackerone.com/reports/3481206 | Permissions Required |