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CVE-2026-1526— undici is vulnerable to Unbounded Memory Consumption in undici WebSocket permessage-deflate Decompression

Quick assessment

Affected
undici undici
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

undici是Node.js开源的一个HTTP/1.1客户端。 undici存在安全漏洞，该漏洞源于在permessage-deflate解压缩期间存在无限制内存消耗，可能导致恶意WebSocket服务器发送小型压缩帧，使Node.js进程耗尽内存并崩溃或无响应。

CVSS 7.5 · High EPSS 1.15% · P66

Affected Version Matrix 2

VendorProduct Version RangeStatus
undici undici < 6.24.0; 7.0.0 < 7.24.0 affected
6.24.0: 7.24.0 unaffected
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I. Basic Information for CVE-2026-1526

Vulnerability Information
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Vulnerability Title
undici is vulnerable to Unbounded Memory Consumption in undici WebSocket permessage-deflate Decompression
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
对高度压缩数据的处理不恰当(数据放大攻击)
Source: CVE Program / CVE List V5
Vulnerability Title
undici 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
undici是Node.js开源的一个HTTP/1.1客户端。 undici存在安全漏洞，该漏洞源于在permessage-deflate解压缩期间存在无限制内存消耗，可能导致恶意WebSocket服务器发送小型压缩帧，使Node.js进程耗尽内存并崩溃或无响应。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
undici undici < 6.24.0; 7.0.0 < 7.24.0 -

II. Public POCs for CVE-2026-1526

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III. Intelligence Information for CVE-2026-1526

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Vendor Advisories for CVE-2026-1526 (1)

Other References for CVE-2026-1526 (1)

Same Patch Batch · undici · 2026-03-12 · 6 CVEs total

CVE-2026-1528 7.5 HIGH undici is vulnerable to Malicious WebSocket 64-bit length overflows undici parser and cras
CVE-2026-2229 7.5 HIGH undici is vulnerable to Unhandled Exception in undici WebSocket Client Due to Invalid serv
CVE-2026-1525 6.5 MEDIUM undici is vulnerable to Inconsistent Interpretation of HTTP Requests ('HTTP Request/Respon
CVE-2026-2581 5.9 MEDIUM undici is vulnerable to Unbounded Memory Consumption in in Undici's DeduplicationHandler v
CVE-2026-1527 4.6 MEDIUM undici is vulnerable to CRLF Injection via upgrade option

IV. Related Vulnerabilities

Same product: undici
Same vendor: undici
Same weakness: CWE-409

V. Comments for CVE-2026-1526

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