CVE-2026-4867 Detail
Received
This CVE record has recently been published to the CVE List and has been included within the NVD dataset. DescriptionImpact: A bad regular expression is generated any time you have three or more parameters within a single segment, separated by something that is not a period (.). For example, /:a-:b-:c or /:a-:b-:c-:d. The backtrack protection added in [email protected] only prevents ambiguity for two parameters. With three or more, the generated lookahead does not block single separator characters, so capture groups overlap and cause catastrophic backtracking. Patches: Upgrade to [email protected] Custom regex patterns in route definitions (e.g., /:a-:b([^-/]+)-:c([^-/]+)) are not affected because they override the default capture group. Workarounds: All versions can be patched by providing a custom regular expression for parameters after the first in a single segment. As long as the custom regular expression does not match the text before the parameter, you will be safe. For example, change /:a-:b-:c to /:a-:b([^-/]+)-:c([^-/]+). If paths cannot be rewritten and versions cannot be upgraded, another alternative is to limit the URL length. Metrics
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CVSS 4.0 Severity and Vector Strings:
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Weakness Enumeration
Quick InfoCVE Dictionary Entry:CVE-2026-4867 NVD Published Date: 03/26/2026 NVD Last Modified: 03/26/2026 Source: openjs |
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