Service interruption via scientific-notation expansion
Published Mar 23, 2026 · Updated Mar 23, 2026
DoS in Rails Active Support before branch fixes 7.2.3.1, 8.0.4.1, and 8.1.2.1 allows remote attackers to interrupt services. The NumberConverter#valid_bigdecimal path passes strings containing e or d notation to BigDecimal, which expands a short exponent into an enormous decimal before formatting. Exploitation requires an application to pass attacker-controlled strings into a number helper; the resulting CPU and memory exhaustion interrupts that application service.
Summary
What happened
DoS in Rails Active Support before branch fixes 7.2.3.1, 8.0.4.1, and 8.1.2.1 allows remote attackers to interrupt services. The NumberConverter#valid_bigdecimal path passes strings containing e or d notation to BigDecimal, which expands a short exponent into an enormous decimal before formatting. Exploitation requires an application to pass attacker-controlled strings into a number helper; the resulting CPU and memory exhaustion interrupts that application service.
The record
- CVE
- CVE-2026-33176
- Published
- Mar 23, 2026
- Updated
- Mar 23, 2026
- Vendor
- Rails
- Product
- Active Support
- Classifications
- CWE-770, CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 23, 2026CVE publishedPublication date reported by the CVE source.
- Mar 23, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 7.2.3.1
- Affected versionversion=>= 8.0.0.beta1, < 8.0.4.1
- Affected versionversion=>= 8.1.0.beta1, < 8.1.2.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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