CVE-2026-1525

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2026-1525
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-1525.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-1525
Aliases
Downstream
Related
Published
2026-03-12T20:16:02.670Z
Modified
2026-04-10T05:37:59.925016Z
Severity
  • 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
Summary
[none]
Details

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 consequences:

  • Denial of Service: Strict HTTP parsers (proxies, servers) will reject requests with duplicate Content-Length headers (400 Bad Request)
  • HTTP Request Smuggling: In deployments where an intermediary and backend interpret duplicate headers inconsistently (e.g., one uses the first value, the other uses the last), this can enable request smuggling attacks leading to ACL bypass, cache poisoning, or credential hijacking
References

Affected packages

Git / github.com/nodejs/undici

Affected ranges

Type
GIT
Repo
https://github.com/nodejs/undici
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
8873c947271faf1ebc455bdc6158ecbc022ecfa9
Introduced
1cfe0949053aac6267f11b919cee9315a27f1fd6
Fixed
07a39067a0485c1953196f500d945fe09378a176
Database specific 
{
    "versions": [
        {
            "introduced": "0"
        },
        {
            "fixed": "6.24.0"
        },
        {
            "introduced": "7.0.0"
        },
        {
            "fixed": "7.24.0"
        }
    ]
}

Affected versions

v1.*
v1.0.0
v1.0.1
v1.0.2
v1.0.3
v1.1.0
v1.2.0
v1.2.1
v1.2.2
v1.2.5
v1.2.6
v1.3.0
v1.3.1
v2.*
v2.0.0
v2.0.1
v2.0.2
v2.0.3
v2.0.4
v2.0.5
v2.0.6
v2.0.7
v2.1.0
v3.*
v3.0.0
v3.1.0
v3.2.0
v3.3.0
v3.3.1
v4.*
v4.0.0
v4.0.0-alpha.0
v4.0.0-alpha.1
v4.0.0-alpha.2
v4.0.0-alpha.4
v4.0.0-alpha.5
v4.0.0-rc.1
v4.0.0-rc.2
v4.0.0-rc.3
v4.0.0-rc.4
v4.0.0-rc.5
v4.0.0-rc.7
v4.0.0-rc.8
v4.1.0
v4.1.1
v4.10.0
v4.10.1
v4.10.2
v4.10.3
v4.10.4
v4.11.0
v4.11.1
v4.11.2
v4.11.3
v4.12.0
v4.12.2
v4.13.0
v4.14.0
v4.14.1
v4.15.0
v4.15.1
v4.16.0
v4.2.1
v4.2.2
v4.3.0
v4.3.1
v4.4.1
v4.4.2
v4.4.3
v4.4.4
v4.4.5
v4.4.6
v4.4.7
v4.5.0
v4.5.1
v4.6.0
v4.7.0
v4.7.1
v4.7.2
v4.7.3
v4.8.0
v4.8.1
v4.8.2
v4.9.0
v4.9.1
v4.9.2
v4.9.3
v4.9.4
v4.9.5
v5.*
v5.0.0
v5.1.0
v5.1.1
v5.10.0
v5.11.0
v5.12.0
v5.13.0
v5.14.0
v5.15.0
v5.15.1
v5.15.2
v5.16.0
v5.17.0
v5.17.1
v5.18.0
v5.19.0
v5.19.1
v5.2.0
v5.20.0
v5.21.0
v5.21.1
v5.21.2
v5.22.0
v5.22.1
v5.23.0
v5.23.4
v5.24.0
v5.25.0
v5.25.1
v5.25.2
v5.25.3
v5.26.0
v5.26.1
v5.26.2
v5.26.3
v5.26.4
v5.26.5
v5.27.0
v5.27.1
v5.27.2
v5.28.0
v5.28.1
v5.28.2
v5.3.0
v5.4.0
v5.5.0
v5.5.1
v5.6.0
v5.6.1
v5.7.0
v5.8.0
v5.8.1
v5.8.2
v5.9.1
v6.*
v6.0.0
v6.0.1
v6.1.0
v6.10.0
v6.10.1
v6.10.2
v6.11.0
v6.11.1
v6.12.0
v6.13.0
v6.14.0
v6.14.1
v6.15.0
v6.16.0
v6.16.1
v6.17.0
v6.18.0
v6.18.1
v6.18.2
v6.19.0
v6.19.1
v6.19.2
v6.19.3
v6.19.4
v6.19.5
v6.19.6
v6.19.7
v6.19.8
v6.2.0
v6.2.1
v6.20.0
v6.20.1
v6.21.0
v6.21.1
v6.21.2
v6.21.3
v6.22.0
v6.23.0
v6.3.0
v6.4.0
v6.5.0
v6.6.0
v6.6.1
v6.6.2
v6.7.0
v6.7.1
v6.8.0
v6.9.0
v7.*
v7.0.0
v7.1.0
v7.1.1
v7.10.0
v7.11.0
v7.12.0
v7.13.0
v7.14.0
v7.15.0
v7.16.0
v7.17.0
v7.18.0
v7.18.1
v7.18.2
v7.19.0
v7.19.1
v7.19.2
v7.2.0
v7.2.1
v7.2.2
v7.2.3
v7.20.0
v7.21.0
v7.22.0
v7.23.0
v7.3.0
v7.4.0
v7.5.0
v7.6.0
v7.7.0
v7.8.0
v7.9.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-1525.json"