CVE Explorer
CVE-2026-1525
Undici allows duplicate HTTP Content-Length headers when they are provided in an array with case-variant names (e.g., Content-Length and content-length). This produces malformed HTTP/1.1 requests with multiple conflicting Content-Length values on the wire.
Who is impacted:
* Applications using undici.request(), undici.Client, or similar low-level APIs with headers passed as flat arrays
* Applications that accept user-controlled header names without case-normalization
Potential conseque
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"collectionURL":"https://github.com/nodejs/undici/","defaultStatus":"unaffected","packageName":"undici","product":"undici","repo":"https://github.com/nodejs/undici/","vendor":"undici","versions":[{"status":"affected","version":"< 6.24.0; 7.0.0 < 7.24.0"},{"status":"unaffected","version":"6.24.0: 7.24.0"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-444","description":"CWE-444 Inconsistent interpretation of HTTP requests ('HTTP Request/Response smuggling')","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/problemTypes/0/descriptions/0
Source references
5 source assertions{"url":"https://cna.openjsf.org/security-advisories.html"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/references/4
{"url":"https://cwe.mitre.org/data/definitions/444.html"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/references/2
{"url":"https://github.com/nodejs/undici/security/advisories/GHSA-2mjp-6q6p-2qxm"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/references/0
{"url":"https://hackerone.com/reports/3556037"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/references/3
{"url":"https://www.rfc-editor.org/rfc/rfc9110.html#section-8.6"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:428aadfc23f3fbad5cbbdd92eafc218afe137d89251060e0b0df4e2504049e29 · sha256:6ac81d7a79799974… · /containers/cna/references/1
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.