{"id":"CVE-2026-1526","title":"The undici WebSocket client is vulnerable to a denial-of-service attack via unbounded memory consumption during permessage-deflate decompression","summary":"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 decompr…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-409","CWE-770"],"vendor":"nodejs","product":"undici","affected":["undici < 6.24.0","undici >= 7.0.0, < 7.24.0"],"patched":["undici 7.24.0"],"published":"2026-03-12","updated":"2026-07-02","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-1526","references":[{"url":"https://cna.openjsf.org/security-advisories.html","label":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://datatracker.ietf.org/doc/html/rfc7692","label":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://github.com/nodejs/undici/security/advisories/GHSA-vrm6-8vpv-qv8q","label":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://hackerone.com/reports/3481206","label":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://access.redhat.com/errata/RHSA-2026:13826","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:17789","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:21772","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:21931","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:34342","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:5807","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7080","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7123","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7302","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7310","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7350","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7670","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7675","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:7983","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:9742","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/security/cve/CVE-2026-1526","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2447142","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1526.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-1526"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-1526"},{"url":"https://access.redhat.com/errata/RHSA-2026:56431"}],"tags":["nvd","csaf","vex","red-hat","cve.org"],"epss":0.0115,"epssPercentile":0.65483,"ingestedAt":"2026-07-02T12:34:40.375Z","ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-03-13T18:04:06.608247Z"},"slug":"CVE-2026-1526","body":"## Overview\n\nThe 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.\n\nThe 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.\n\n## Affected\n\n- `undici < 6.24.0`\n- `undici >= 7.0.0, < 7.24.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `undici 7.24.0`\n\n## Vendor advisories\n\n- **RHSA-2026:17789** · Red Hat · fixed in: Cryostat 4 on RHEL 9 · released 2026-05-26 · [advisory](https://access.redhat.com/errata/RHSA-2026:17789)\n- **RHSA-2026:7310** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0) · released 2026-04-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:7310)\n- **RHSA-2026:7080** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-04-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:7080)\n- **RHSA-2026:7675** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10) · released 2026-04-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:7675)\n- **RHSA-2026:7123** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8) · released 2026-04-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:7123)\n- **RHSA-2026:7670** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 8) · released 2026-04-13 · [advisory](https://access.redhat.com/errata/RHSA-2026:7670)\n- **RHSA-2026:7983** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6) · released 2026-04-14 · [advisory](https://access.redhat.com/errata/RHSA-2026:7983)\n- **RHSA-2026:7302** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-04-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:7302)\n- **RHSA-2026:7350** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9) · released 2026-04-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:7350)\n- **RHSA-2026:34342** · Red Hat · fixed in: Cluster Observability Operator 1.5.0 · released 2026-07-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:34342)\n- **RHSA-2026:9742** · Red Hat · fixed in: Red Hat Developer Hub 1.8 · released 2026-04-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:9742)\n- **Red Hat VEX** · Important · affected: OpenShift Lightspeed, OpenShift Pipelines, Red Hat Developer Hub, Red Hat OpenShift AI (RHOAI), Red Hat OpenShift Dev Spaces, Self-service automation portal 2 · no fix planned: Red Hat Developer Hub, OpenShift Lightspeed, OpenShift Pipelines, Red Hat OpenShift AI (RHOAI), … · updated 2026-09-12 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1526.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}