CVE-2020-37056
CVE-2020-37056 is a critical-severity vulnerability with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-290.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v4: 6.9
- EPSS exploit prediction: 1% (41st percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2020-30926
- Weakness: CWE-290
- Published:
- Last modified:
Description
Crystal Shard http-protection 0.2.0 contains an IP spoofing vulnerability that allows attackers to bypass protection middleware by manipulating request headers. Attackers can hardcode consistent IP values across X-Forwarded-For, X-Client-IP, and X-Real-IP headers to circumvent security checks and gain unauthorized access.
Frequently asked questions
- What is CVE-2020-37056?
- Crystal Shard http-protection 0.2.0 contains an IP spoofing vulnerability that allows attackers to bypass protection middleware by manipulating request headers. Attackers can hardcode consistent IP values across X-Forwarded-For, X-Client-IP, and X-Real-IP headers to circumvent security checks and gain unauthorized access.
- How severe is CVE-2020-37056?
- CVE-2020-37056 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2020-37056 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2020-37056?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2020-37056 have an EU (EUVD) identifier?
- Yes. CVE-2020-37056 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2020-30926.
- When was CVE-2020-37056 published?
- CVE-2020-37056 was published on 2026-01-30 and last updated on 2026-06-17.
References
- https://github.com/rogeriozambon/http-protection
- https://www.exploit-db.com/exploits/48533
- https://www.vulncheck.com/advisories/crystal-shard-http-protection-ip-spoofing-bypass
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