CVE-2026-11525

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Source
https://cve.org/CVERecord?id=CVE-2026-11525
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11525.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-11525
Aliases
Downstream
AZL (1)
CGA (75)
CLEANSTART (7)
CLSA (5)
DEBIAN (1)
ECHO (1)
MINI (16)
openSUSE (3)
RHSA (8)
RLSA (6)
ROOT (1)
SUSE (10)
UBUNTU (1)
Related
ALSA (6)
openSUSE (3)
SUSE (10)
Published
2026-06-17T17:31:03Z
Modified
2026-09-29T09:26:40Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS Calculator
Summary
undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matching
Details

Impact: When undici parses a Set-Cookie header, it accepts any SameSite attribute value that contains Strict, Lax, or None as a substring, rather than the case-insensitive exact match specified by RFC 6265. Non-spec values are silently mapped to one of the three standard tokens. For example, SameSite=NoneOfYourBusiness is parsed as None (the most permissive setting), and SameSite=StrictLax is parsed as Lax (a downgrade from Strict).

Affected applications are those that consume Set-Cookie headers from server responses (for example via undici's fetch or proxy code paths) and then forward or rely on the parsed sameSite attribute. A malicious or non-compliant server can coerce the consumer's view of a cookie's SameSite policy to a weaker value, silently degrading the SameSite enforcement the cookie is supposed to provide.

This was introduced in undici 5.15.0 when the cookies feature was added.

Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0.

Workarounds: After parsing a Set-Cookie header, validate that the resulting sameSite attribute is one of 'Strict', 'Lax', or 'None' (exact, case-insensitive) before forwarding or relying on it.

Database specific 
{
    "cna_assigner":  "openjs",
    "cwe_ids":  [
        "CWE-183"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/11xxx/CVE-2026-11525.json"
}
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
551138cbc1742c92242a68216167761075e8a82c
Introduced
1cfe0949053aac6267f11b919cee9315a27f1fd6
Fixed
f9eba0ad9134e1c0977848476bba9d49734696e4
Introduced
d7fbba51772deecb830a297647456a5e9f9fec57
Fixed
a0806e1f66a83db0a792b8407c2e97fcf8ed58af
Database specific
Show details 
{
    "cpe":  "cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*",
    "extracted_events":  [
        {
            "introduced":  "0"
        },
        {
            "fixed":  "6.27.0"
        },
        {
            "introduced":  "7.0.0"
        },
        {
            "fixed":  "7.28.0"
        },
        {
            "introduced":  "8.0.0"
        },
        {
            "fixed":  "8.5.0"
        }
    ],
    "source":  "CPE_RANGE"
}

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
v6.24.0
v6.24.1
v6.25.0
v6.26.0
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
v7.24.0
v7.24.1
v7.24.2
v7.24.3
v7.24.4
v7.24.5
v7.24.6
v7.24.7
v7.24.8
v7.25.0
v7.26.0
v7.27.0
v7.27.1
v7.27.2
v7.3.0
v7.4.0
v7.5.0
v7.6.0
v7.7.0
v7.8.0
v7.9.0
v8.*
v8.0.0
v8.0.1
v8.0.2
v8.0.3
v8.1.0
v8.2.0
v8.3.0
v8.4.0
v8.4.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11525.json"