CVE Explorer
CVE-2026-1527
ImpactWhen an application passes user-controlled input to the upgrade option of client.request(), an attacker can inject CRLF sequences (\r\n) to:
* Inject arbitrary HTTP headers
* Terminate the HTTP request prematurely and smuggle raw data to non-HTTP services (Redis, Memcached, Elasticsearch)
The vulnerability exists because undici writes the upgrade value directly to the socket without validating for invalid header characters:
// lib/dispatcher/client-h1.js:1121
if (upgrade) {
heade
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:v2:73ffdae2c7d73cee5c9f03617c070acb7e71749aaa03d32d70bdb2dfed6f02eb · sha256:c8edfa6ec64d5b79… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.6,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N","version":"3.1"},"metric_type":"cvssV3_1"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:73ffdae2c7d73cee5c9f03617c070acb7e71749aaa03d32d70bdb2dfed6f02eb · sha256:c8edfa6ec64d5b79… · /containers/cna/metrics/0/cvssV3_1
CWE assertions
1 source assertion{"cweId":"CWE-93","description":"CWE-93 Improper neutralization of CRLF sequences ('CRLF injection')","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:73ffdae2c7d73cee5c9f03617c070acb7e71749aaa03d32d70bdb2dfed6f02eb · sha256:c8edfa6ec64d5b79… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"url":"https://cna.openjsf.org/security-advisories.html"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:73ffdae2c7d73cee5c9f03617c070acb7e71749aaa03d32d70bdb2dfed6f02eb · sha256:c8edfa6ec64d5b79… · /containers/cna/references/2
{"url":"https://github.com/nodejs/undici/security/advisories/GHSA-4992-7rv2-5pvq"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:73ffdae2c7d73cee5c9f03617c070acb7e71749aaa03d32d70bdb2dfed6f02eb · sha256:c8edfa6ec64d5b79… · /containers/cna/references/0
{"url":"https://hackerone.com/reports/3487198"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:73ffdae2c7d73cee5c9f03617c070acb7e71749aaa03d32d70bdb2dfed6f02eb · sha256:c8edfa6ec64d5b79… · /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.