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TI-2026-08490 Aliases CVE-2026-9679GHSA-p88m-4jfj-68fv

undici vulnerable to HTTP header injection via Set-Cookie percent-decoding

Priority LOW 26CWE-93Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Partial Red Hat: 2 fixed, 14 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

Impact: undici's cookie parser in parseSetCookie percent-decodes cookie values via qsUnescape, turning encoded sequences like %0D%0A, %00, %3B, and %3D into their literal byte equivalents. RFC 6265 §5.4 does not specify any decoding and browsers do not decode either. Applications that parse a Set-Cookie header and then forward the parsed value into a response header (proxies, middleware, SSR frameworks) become vulnerable to HTTP response header injection: an attacker-controlled upstream can inject arbitrary Set-Cookie, Location, or Cache-Control headers into the application's downstream response, enabling session fixation, open redirect, or cache poisoning. Affected applications are those that use undici's cookie parsing (parseSetCookie, parseCookie, getSetCookies) and forward the parsed cookie value into a response header. This was introduced in undici 7.0.0 via PR #3789. Patches: Upgrade to undici v6.26.0, v7.28.0 or v8.5.0. Workarounds: If upgrade is not immediately possible, do not forward values returned by parseSetCookie/parseCookie/getSetCookies directly into response headers; sanitize the value first to strip or reject CR, LF, NUL, ;, and = bytes.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00257 17th percentileScored 2026-11-07
Fix Partial undici (undici): 6.26.0, 7.28.0, 8.5.0undici (npm): 6.27.0, 7.28.0, 8.5.0Red Hat: 3 advisoriesRed Hat: 2 fixed, 14 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
NodeJSundicibefore 6.26.0; 7.0.0 to before 7.28.0; 8.0.0 to before 8.5.06.26.0, 7.28.0, 8.5.0Patch availableCNA
—undici (npm)before 6.27.06.27.0Patch availableGHSA-p88m-4jfj-68fv
—undici (npm)7.0.0 to before 7.28.07.28.0Patch availableGHSA-p88m-4jfj-68fv
—undici (npm)8.0.0 to before 8.5.08.5.0Patch availableGHSA-p88m-4jfj-68fv
  • undici VendorNodeJS Affected before 6.26.0; 7.0.0 to before 7.28.0; 8.0.0 to before 8.5.0 Fixed in 6.26.0, 7.28.0, 8.5.0 Patch available CNA
  • undici (npm) Vendor— Affected before 6.27.0 Fixed in 6.27.0 Patch available GHSA-p88m-4jfj-68fv
  • undici (npm) Vendor— Affected 7.0.0 to before 7.28.0 Fixed in 7.28.0 Patch available GHSA-p88m-4jfj-68fv
  • undici (npm) Vendor— Affected 8.0.0 to before 8.5.0 Fixed in 8.5.0 Patch available GHSA-p88m-4jfj-68fv

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:*before 6.27.0; 7.0.0 to before 7.28.0; 8.0.0 to before 8.5.0VulnerableNodeJS
  • cpe:2.3:a:nodejs:undici:*:*:*:*:*:node.js:*:* Versions before 6.27.0; 7.0.0 to before 7.28.0; 8.0.0 to before 8.5.0 Vulnerable ·NodeJS

Remediation

  • Fix · CNA undici (undici) Fixed in 6.26.0, 7.28.0, 8.5.0
  • Fix · GHSA-p88m-4jfj-68fv undici (npm) Fixed in 6.27.0 Advisory →
  • Fix · GHSA-p88m-4jfj-68fv undici (npm) Fixed in 7.28.0 Advisory →
  • Fix · GHSA-p88m-4jfj-68fv undici (npm) Fixed in 8.5.0 Advisory →

Red Hat 3 advisories

  • RHSA-2026:56431 Released 2026-08-18 · Red Hat rating Important
    Red Hat OpenShift Data Foundation 4.18.27 security, enhancement & bug fix update
    • Red Hat Openshift Data Foundation 4.18 registry.redhat.io/odf4/cephcsi-rhel9, registry.redhat.io/odf4/cephcsi-rhel9-operator, registry.redhat.io/odf4/mcg-core-rhel9 +16
  • RHSA-2026:38236 Released 2026-07-11 · Red Hat rating Important
    Red Hat Hardened Images RPMs Security Update
    • Red Hat Hardened Images nodejs24-1:24.18.0-0.3.hum1@aarch64, nodejs24-1:24.18.0-0.3.hum1@src, nodejs24-1:24.18.0-0.3.hum1@x86_64 +16
  • RHSA-2026:38009 Released 2026-07-10 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images nodejs26-1:26.5.0-1.3.hum1@aarch64, nodejs26-1:26.5.0-1.3.hum1@src, nodejs26-1:26.5.0-1.3.hum1@x86_64 +14

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    undici 6.26.0, 7.28.0, 8.5.0

    4 records Highest priority Priority MEDIUM 1 MEDIUM, 3 LOW

    Other records, highest priority first

    • TI-2026-10459 undici WebSocket client vulnerable to denial of service via fragment count bypassPriority MEDIUM 40
    • TI-2026-09954 undici vulnerable to Set-Cookie SameSite attribute downgrade via permissive substring matchingPriority LOW 17
    • TI-2026-05899 undici vulnerable to HTTP response queue poisoning via keep-alive socket reusePriority LOW 17
    Show all 4 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Cryostat 4AffectedNo fix yet: Fix deferred
OpenShift PipelinesAffectedNo fix yet: Fix deferred
Red Hat AMQ Broker 7AffectedNo fix yet: Fix deferred
Red Hat Build of Podman DesktopAffectedNo fix yet: Fix deferred
Red Hat Developer Hub 1AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesAffectedNo fix planned: Will not fix
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred
Red Hat OpenShift Dev SpacesAffectedNo fix yet: Fix deferred
Self-service automation portal 2AffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesFixed RHSA-2026:38009, RHSA-2026:38236
Red Hat Openshift Data Foundation 4.18Fixed RHSA-2026:56431
Not affected: 2 products
  • Red Hat Hardened Images
  • Red Hat Openshift Data Foundation 4.18

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-9679
  2. 2026-10-03 Alias added: GHSA-p88m-4jfj-68fv
  3. 2026-10-27 Affected versions changed · Red Hat
  4. 2026-11-06 Affected versions changed · Red Hat

References

Advisory 3

Other 1

  • TI-2026-01215 undici is vulnerable to Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') CVSS 3.1CRITICAL 9.8
  • TI-2022-16376 `undici.request` vulnerable to SSRF using absolute URL on `pathname` CVSS 3.1CRITICAL 9.8
  • TI-2023-09734 CRLF Injection in Nodejs ‘undici’ via host CVSS 3.1MEDIUM 6.5
  • TI-2022-13193 CRLF injection in request headers CVSS 3.1MEDIUM 6.5
  • TI-2022-16375 CRLF Injection in Nodejs ‘undici’ via Content-Type CVSS 3.1MEDIUM 5.3
  • TI-2022-13194 Uncleared cookies on cross-host/cross-origin redirect in undici CVSS 3.1MEDIUM 6.5
See all 51 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences