undici vulnerable to HTTP header injection via Set-Cookie percent-decoding
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.
- Published
- Jun 17, 2026
- Updated
- Jun 25, 2026
- EPSS
- 0.3% · 24th percentile
- CWE
- CWE-93
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Report tools
Action score
23
Monitor
Low priority for now.
- CVSS
- 23 / 40 · 5.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · openjs
- 5.9
- NVD has not scored this yet; the score shown is the CNA’s.
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| nodejs | undici | cpe:2.3:a:nodejs:undici |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- nodejs undicibefore 6.27.0
- nodejs undici7.0.0 and later · before 7.28.0
- nodejs undici8.0.0 and later · before 8.5.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (openjs). Independent of NVD's CPE analysis and usually ahead of it.
undici undici
- 6.26.0, 7.28.0, 8.5.0not affected
- before 6.26.0affected · semver
- 7.0.0 and later · before 7.28.0affected · semver
- 8.0.0 and later · before 8.5.0affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:13 | node-undici | all versions | — |
| Debian:14 | node-undici | before 8.5.0+dfsg+~cs3.2.0-1 | 8.5.0+dfsg+~cs3.2.0-1 |
| npm | undici | from 7.0.0 · before 7.28.0 | 7.28.0 |
| npm | undici | from 8.0.0 · before 8.5.0 | 8.5.0 |
| npm | undici | before 6.27.0 | 6.27.0 |
| Red Hat:hummingbird:1 | nodejs24 | before 0:24.18.0-0.3.hum1 | 0:24.18.0-0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs24-bin | before 0:24.18.0-0.3.hum1 | 0:24.18.0-0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs24-devel | before 0:24.18.0-0.3.hum1 | 0:24.18.0-0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs24-docs | before 0:24.18.0-0.3.hum1 | 0:24.18.0-0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs24-full-i18n | before 0:24.18.0-0.3.hum1 | 0:24.18.0-0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs24-libs | before 0:24.18.0-0.3.hum1 | 0:24.18.0-0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs24-npm | before 0:11.16.0-1.24.18.0.0.3.hum1 | 0:11.16.0-1.24.18.0.0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs24-npm-bin | before 0:24.18.0-0.3.hum1 | 0:24.18.0-0.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26 | before 0:26.5.0-1.3.hum1 | 0:26.5.0-1.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26-bin | before 0:26.5.0-1.3.hum1 | 0:26.5.0-1.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26-devel | before 0:26.5.0-1.3.hum1 | 0:26.5.0-1.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26-docs | before 0:26.5.0-1.3.hum1 | 0:26.5.0-1.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26-full-i18n | before 0:26.5.0-1.3.hum1 | 0:26.5.0-1.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26-libs | before 0:26.5.0-1.3.hum1 | 0:26.5.0-1.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26-npm | before 0:11.17.0-1.26.5.0.1.3.hum1 | 0:11.17.0-1.26.5.0.1.3.hum1 |
| Red Hat:hummingbird:1 | nodejs26-npm-bin | before 0:26.5.0-1.3.hum1 | 0:26.5.0-1.3.hum1 |
| Red Hat:hummingbird:1 | v8-13.6-devel | before 0:13.6.233.17-1.24.18.0.0.3.hum1 | 0:13.6.233.17-1.24.18.0.0.3.hum1 |
| SUSE:Linux Enterprise Module for Web and Scripting 15 SP7 | nodejs22 | before 22.23.0-150700.3.12.1 | 22.23.0-150700.3.12.1 |
| SUSE:Linux Enterprise Server 15 SP6-LTSS | nodejs22 | before 22.23.0-150600.13.18.1 | 22.23.0-150600.13.18.1 |
Same product
nodejs: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-35949`undici.request` vulnerable to SSRF using absolute URL on `pathname`40Plan
- CVE-2026-1525undici is vulnerable to Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')39Monitor
- CVE-2026-84961undici vulnerable to TLS certificate validation bypass via dropped connect options in BalancedPool36Monitor
- CVE-2026-13697undici vulnerable to cross-user information disclosure and parse-time crash via degenerate private cache directives36Monitor
- CVE-2026-6734undici vulnerable to cross-origin request routing via SOCKS5 proxy pool reuse35Monitor
- CVE-2026-84933undici vulnerable to cross-user cookie disclosure via Set-Cookie caching in shared caches32Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| undici undici | 6.26.0 | Vendor (CNA) |
| undici undici | 7.28.0 | Vendor (CNA) |
| undici undici | 8.5.0 | Vendor (CNA) |
| debian:node-undici | 8.5.0+dfsg+~cs3.2.0-1 · Debian:14 | Package registry (OSV) |
| npm:undici | 6.27.0 | Package registry (OSV) |
| npm:undici | 7.28.0 | Package registry (OSV) |
| npm:undici | 8.5.0 | Package registry (OSV) |
| red hat:nodejs24 | 0:24.18.0-0.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs24-bin | 0:24.18.0-0.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs24-devel | 0:24.18.0-0.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs24-docs | 0:24.18.0-0.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26 | 0:26.5.0-1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26-bin | 0:26.5.0-1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26-devel | 0:26.5.0-1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26-docs | 0:26.5.0-1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26-full-i18n | 0:26.5.0-1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26-libs | 0:26.5.0-1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26-npm | 0:11.17.0-1.26.5.0.1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| red hat:nodejs26-npm-bin | 0:26.5.0-1.3.hum1 · Red Hat:hummingbird:1 | Package registry (OSV) |
| suse:nodejs22 | 22.23.0-150600.13.18.1 · SUSE:Linux Enterprise Server 15 SP6-LTSS | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- tndud042713reporter
- mcollinaremediation developer
- KhafraDevremediation reviewer
- UlisesGasconremediation reviewer
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-1515742 days apartundici vulnerable to CRLF Injection via blob-like body 'type' property21Monitor
- CVE-2026-152797 days apartundici is vulnerable to CRLF Injection via upgrade option18Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-26-0409 · Jun 19, 2026(OpenJS / Node.js Undici Güvenlik Bildirimi)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-93 · Improper Neutralization of CRLF Sequences ('CRLF Injection')CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- cna.openjsf.org/security-advisories.html
- github.com/nodejs/undici/security/advisories/GHSA-p88m-4jfj-68fv
Vendor advisories and official records. Exploit/PoC links are deliberately left out.