CVE Explorer
CVE-2026-26961
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Multipart::Parser extracts the boundary parameter from multipart/form-data using a greedy regular expression. When a Content-Type header contains multiple boundary parameters, Rack selects the last one rather than the first. In deployments where an upstream proxy, WAF, or intermediary interprets the first boundary parameter, this mismatch can allow an attacker to smuggle multipart content past upstrea
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"product":"rack","vendor":"rack","versions":[{"status":"affected","version":"< 2.2.23"},{"status":"affected","version":">= 3.0.0.beta1, < 3.1.21"},{"status":"affected","version":">= 3.2.0, < 3.2.6"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:adfacbfa464ee5378a9024e586e6a59d0ff7844a960121c9005462331d34c566 · sha256:44a475d0f32c668b… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":3.7,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:adfacbfa464ee5378a9024e586e6a59d0ff7844a960121c9005462331d34c566 · sha256:44a475d0f32c668b… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-436","description":"CWE-436: Interpretation Conflict","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:adfacbfa464ee5378a9024e586e6a59d0ff7844a960121c9005462331d34c566 · sha256:44a475d0f32c668b… · /containers/cna/problemTypes/0/descriptions/0
Source references
1 source assertion{"name":"https://github.com/rack/rack/security/advisories/GHSA-vgpv-f759-9wx3","tags":["x_refsource_CONFIRM"],"url":"https://github.com/rack/rack/security/advisories/GHSA-vgpv-f759-9wx3"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:adfacbfa464ee5378a9024e586e6a59d0ff7844a960121c9005462331d34c566 · sha256:44a475d0f32c668b… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.