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CVE

CVE-2023-27539

There is a denial of service vulnerability in the header parsing component of Rack.

There is a denial of service vulnerability in the header parsing component of Rack.

MEDIUM · CVSS 5.3 EPSS 0.00364
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
▤

Affected Products & Versions

3
rack>= 2.0.0 and < 2.2.6.4
rack>= 3.0.0 and < 3.0.6.1
debian linuxall versions
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
RubyGems rack LOW fixed in 2.2.6.4
▣

Scoring & Timeline

5.3
MEDIUM · CVSS v3.1 · support@hackerone.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD09 Jan 2025 · 01:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

21
suse-csafopenSUSE-SU-2026:10358-1
suse-csafopenSUSE-SU-2026:10286-1
suse-csafopenSUSE-SU-2025:14875-1
suse-csafopenSUSE-SU-2025:14811-1
usnUSN-7036-1
🔗

References & Sources

7
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://discuss.rubyonrails.org/t/cve-2023-27539-possible-denial-of-service-vulnerability-in-racks-header-parsing/82466Vendor Advisory
https://github.com/advisories/GHSA-c6qg-cjj8-47qpPatchThird Party Advisory
https://github.com/rack/rack/commit/231ef369ad0b542575fb36c74fcfcfabcf6c530cPatch
https://github.com/rack/rack/commit/ee7919ea04303717858be1c3f16b406adc6d8cffPatch
https://lists.debian.org/debian-lts-announce/2023/04/msg00017.htmlMailing ListThird Party Advisory
https://security.netapp.com/advisory/ntap-20231208-0016/Third Party Advisory
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