CVE-2023-27539
CVE-2023-27539 is a medium-severity vulnerability in Rack with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: Medium (CVSS 3.x base score 5.3)
- EPSS exploit prediction: 1% (61st percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2023-0979
- Affected product: Rack
- Published:
- Last modified:
Description
There is a denial of service vulnerability in the header parsing component of Rack.
Frequently asked questions
- What is CVE-2023-27539?
- There is a denial of service vulnerability in the header parsing component of Rack.
- How severe is CVE-2023-27539?
- CVE-2023-27539 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
- Is CVE-2023-27539 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2023-27539?
- CVE-2023-27539 primarily affects Rack. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2023-27539?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2023-27539 have an EU (EUVD) identifier?
- Yes. CVE-2023-27539 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2023-0979.
- When was CVE-2023-27539 published?
- CVE-2023-27539 was published on 2025-01-09 and last updated on 2026-06-17.
References
- https://discuss.rubyonrails.org/t/cve-2023-27539-possible-denial-of-service-vulnerability-in-racks-header-parsing/82466
- https://github.com/advisories/GHSA-c6qg-cjj8-47qp
- https://github.com/rack/rack/commit/231ef369ad0b542575fb36c74fcfcfabcf6c530c
- https://github.com/rack/rack/commit/ee7919ea04303717858be1c3f16b406adc6d8cff
- https://lists.debian.org/debian-lts-announce/2023/04/msg00017.html
- https://security.netapp.com/advisory/ntap-20231208-0016/
- https://www.debian.org/security/2023/dsa-5530
Affected products (3)
- cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
- cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
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