{"id":"CVE-2026-4926","title":"Impact:\n\nA bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`","summary":"Impact:\n\nA bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of servic…","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-400","CWE-1333"],"vendor":"pillarjs","product":"path-to-regexp","affected":["path-to-regexp >= 8.0.0, < 8.4.0"],"patched":["path-to-regexp 8.4.0"],"published":"2026-03-26","updated":"2026-09-09","sourceUpdated":"2026-09-09T13:20:25.320","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-4926","references":[{"url":"https://cna.openjsf.org/security-advisories.html","label":"ce714d77-add3-4f53-aff5-83d477b104bb"},{"url":"https://access.redhat.com/errata/RHSA-2026:10153","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:10172","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:10175","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:13545","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"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-2026:19409","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:19410","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:24761","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:24762","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:24866","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:36651","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:40118","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:40945","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:50300","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:65126","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://access.redhat.com/errata/RHSA-2026:9385","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-2026-4926","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2451867","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4926.json","label":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-4926"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4926"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-03-27T19:44:44.790485Z"},"epss":0.00791,"epssPercentile":0.54342,"ingestedAt":"2026-07-10T01:55:22.976Z","slug":"CVE-2026-4926","body":"## Overview\n\nImpact:\n\nA bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service.\n\nPatches:\n\nFixed in version 8.4.0.\n\nWorkarounds:\n\nLimit the number of sequential optional groups in route patterns. Avoid passing user-controlled input as route patterns.\n\n## Affected\n\n- `path-to-regexp >= 8.0.0, < 8.4.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `path-to-regexp 8.4.0`\n\n## Vendor advisories\n\n- **RHSA-2026:24761** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.5 for RHEL 8, Red Hat Ansible Automation Platform 2.5 for RHEL 9 · released 2026-06-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:24761)\n- **RHSA-2026:24762** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.6 for RHEL 9 · released 2026-06-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:24762)\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-2026:19409** · Red Hat · fixed in: Migration Toolkit for Virtualization 2.1 · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19409)\n- **RHSA-2026:19410** · Red Hat · fixed in: Migration Toolkit for Virtualization 2.9 · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19410)\n- **RHSA-2026:24866** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.6 · released 2026-06-09 · [advisory](https://access.redhat.com/errata/RHSA-2026:24866)\n- **RHSA-2026:13545** · Red Hat · fixed in: Red Hat Ansible Automation Platform 2.6 · released 2026-05-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:13545)\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- **RHSA-2026:13826** · Red Hat · fixed in: Red Hat Developer Hub 1.9 · released 2026-05-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:13826)\n- **RHSA-2026:36651** · Red Hat · fixed in: Red Hat Edge Manager 1.0 · released 2026-07-08 · [advisory](https://access.redhat.com/errata/RHSA-2026:36651)\n- **RHSA-2026:40945** · Red Hat · fixed in: Red Hat Edge Manager 1.1 · released 2026-07-16 · [advisory](https://access.redhat.com/errata/RHSA-2026:40945)\n- **Red Hat VEX** · Important · affected: Logging Subsystem for Red Hat OpenShift, OpenShift Pipelines, Red Hat AMQ Broker 7, Red Hat Ansible Automation Platform 2, Red Hat Build of Podman Desktop, Red Hat Data Grid 8, … · no fix planned: Logging Subsystem for Red Hat OpenShift, OpenShift Pipelines, Red Hat AMQ Broker 7, Red Hat Ansible Automation Platform 2, … · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4926.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.2,"exploitation":0,"ransomware":0},"changes":[]}