CVE-2026-2229: undici is vulnerable to Unhandled Exception in undici WebSocket Client Due to Invalid server_max_window_bits Validation
Noroxi assessment
Priority: Monitor (action score 30/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.89% (FIRST EPSS); higher than 59.1% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: nodejs-docs (AlmaLinux:10) 1:22.22.2-1.el10_1; nodejs24-docs (AlmaLinux:10) 1:24.14.1-2.el10_1; nodejs24-npm (AlmaLinux:10) 1:11.11.0-1.24.14.1.2.el10_1.
Low priority for now. Upgrade to nodejs-docs (AlmaLinux:10) 1:22.22.2-1.el10_1; nodejs24-docs (AlmaLinux:10) 1:24.14.1-2.el10_1; nodejs24-npm (AlmaLinux:10) 1:11.11.0-1.24.14.1.2.el10_1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
ImpactThe undici WebSocket client is vulnerable to a denial-of-service attack due to improper validation of the server_max_window_bits parameter in the permessage-deflate extension. When a WebSocket client connects to a server, it automatically advertises support for permessage-deflate compression. A malicious server can respond with an out-of-range server_max_window_bits value (outside zlib's valid range of 8-15). When the server subsequently sends a compressed frame, the client attempts to create a zlib InflateRaw instance with the invalid windowBits value, causing a synchronous RangeError exception that is not caught, resulting in immediate process termination. The vulnerability exists because: * The isValidClientWindowBits() function only validates that the value contains ASCII digits, not that it falls within the valid range 8-15 * The createInflateRaw() call is not wrapped in a try-catch block * The resulting exception propagates up through the call stack and crashes the Node.js process
- GHSA-v9p9-hfj2-hcw8
- ALSA-2026:7080
- ALSA-2026:7123
- ALSA-2026:7350
- ALSA-2026:7670
- ALSA-2026:7675
- RHSA-2026:7080
- RHSA-2026:7123
- RHSA-2026:7302
- RHSA-2026:7310
- RHSA-2026:7350
- RHSA-2026:7670
- RHSA-2026:7675
- RHSA-2026:7983
- RLSA-2026:7080
- RLSA-2026:7123
- RLSA-2026:7302
- RLSA-2026:7350
- RLSA-2026:7670
- RLSA-2026:7675
- Published
- Mar 12, 2026
- Updated
- Sep 14, 2026
- EPSS
- 0.8% · 59th percentile
- CWE
- CWE-248
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.8%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · openjs
- 7.5
- 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.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| 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 6.24.0
- nodejs undici7.0.0 and later · before 7.24.0
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
- 6.24.0: 7.24.0not affected
- < 6.24.0; 7.0.0 < 7.24.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:10 | nodejs-docs | before 1:22.22.2-1.el10_1 | 1:22.22.2-1.el10_1 |
| AlmaLinux:10 | nodejs24-docs | before 1:24.14.1-2.el10_1 | 1:24.14.1-2.el10_1 |
| AlmaLinux:10 | nodejs24-npm | before 1:11.11.0-1.24.14.1.2.el10_1 | 1:11.11.0-1.24.14.1.2.el10_1 |
| AlmaLinux:8 | nodejs | before 1:22.22.2-1.module_el8.10.0+4158+e796f37f | 1:22.22.2-1.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | nodejs | before 1:24.14.1-2.module_el8.10.0+4160+4819ac42 | 1:24.14.1-2.module_el8.10.0+4160+4819ac42 |
| AlmaLinux:8 | nodejs-devel | before 1:22.22.2-1.module_el8.10.0+4158+e796f37f | 1:22.22.2-1.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | nodejs-devel | before 1:24.14.1-2.module_el8.10.0+4160+4819ac42 | 1:24.14.1-2.module_el8.10.0+4160+4819ac42 |
| AlmaLinux:8 | nodejs-docs | before 1:24.14.1-2.module_el8.10.0+4160+4819ac42 | 1:24.14.1-2.module_el8.10.0+4160+4819ac42 |
| AlmaLinux:8 | nodejs-docs | before 1:22.22.2-1.module_el8.10.0+4158+e796f37f | 1:22.22.2-1.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | nodejs-full-i18n | before 1:24.14.1-2.module_el8.10.0+4160+4819ac42 | 1:24.14.1-2.module_el8.10.0+4160+4819ac42 |
| AlmaLinux:8 | nodejs-full-i18n | before 1:22.22.2-1.module_el8.10.0+4158+e796f37f | 1:22.22.2-1.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | nodejs-libs | before 1:24.14.1-2.module_el8.10.0+4160+4819ac42 | 1:24.14.1-2.module_el8.10.0+4160+4819ac42 |
| AlmaLinux:8 | nodejs-libs | before 1:22.22.2-1.module_el8.10.0+4158+e796f37f | 1:22.22.2-1.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | nodejs-nodemon | before 3.0.1-1.module_el8.10.0+4006+3c416519 | 3.0.1-1.module_el8.10.0+4006+3c416519 |
| AlmaLinux:8 | nodejs-nodemon | before 3.0.3-1.module_el8.10.0+4061+f8ceeab9 | 3.0.3-1.module_el8.10.0+4061+f8ceeab9 |
| AlmaLinux:8 | nodejs-packaging | before 2021.06-6.module_el8.10.0+4086+70facd4a | 2021.06-6.module_el8.10.0+4086+70facd4a |
| AlmaLinux:8 | nodejs-packaging | before 2021.06-6.module_el8.10.0+4158+e796f37f | 2021.06-6.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | nodejs-packaging-bundler | before 2021.06-6.module_el8.10.0+4158+e796f37f | 2021.06-6.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | nodejs-packaging-bundler | before 2021.06-6.module_el8.10.0+4086+70facd4a | 2021.06-6.module_el8.10.0+4086+70facd4a |
| AlmaLinux:8 | npm | before 1:10.9.7-1.22.22.2.1.module_el8.10.0+4158+e796f37f | 1:10.9.7-1.22.22.2.1.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | npm | before 1:11.11.0-1.24.14.1.2.module_el8.10.0+4160+4819ac42 | 1:11.11.0-1.24.14.1.2.module_el8.10.0+4160+4819ac42 |
| AlmaLinux:8 | v8-12.4-devel | before 3:12.4.254.21-1.22.22.2.1.module_el8.10.0+4158+e796f37f | 3:12.4.254.21-1.22.22.2.1.module_el8.10.0+4158+e796f37f |
| AlmaLinux:8 | v8-13.6-devel | before 3:13.6.233.17-1.24.14.1.2.module_el8.10.0+4160+4819ac42 | 3:13.6.233.17-1.24.14.1.2.module_el8.10.0+4160+4819ac42 |
| AlmaLinux:9 | nodejs | before 1:24.14.1-2.module_el9.7.0+222+ef1c61e1 | 1:24.14.1-2.module_el9.7.0+222+ef1c61e1 |
+96
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-2026-109829undici vulnerable to cache poisoning and cross-user disclosure via cross-origin redirects36Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-1527Mar 12, 2026 · undici is vulnerable to CRLF Injection via upgrade option18Monitor
- ← EarlierCVE-2026-1528Mar 12, 2026 · undici is vulnerable to Malicious WebSocket 64-bit length overflows undici parser and crashes the client30Monitor
- Later →CVE-2026-2581Mar 12, 2026 · undici is vulnerable to Unbounded Memory Consumption in in Undici's DeduplicationHandler via Response Buffering leads to DoS23Monitor
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 |
|---|---|---|
| almalinux:nodejs | 1:22.22.2-1.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:nodejs-devel | 1:22.22.2-1.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:nodejs-docs | 1:22.22.2-1.el10_1 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:nodejs-full-i18n | 1:22.22.2-1.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:nodejs-libs | 1:22.22.2-1.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:nodejs-nodemon | 3.0.1-1.module_el8.10.0+4006+3c416519 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:nodejs-packaging | 2021.06-6.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:nodejs-packaging-bundler | 2021.06-6.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:nodejs24-docs | 1:24.14.1-2.el10_1 · AlmaLinux:10 | Package registry (OSV) |
| almalinux:npm | 1:10.9.7-1.22.22.2.1.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:v8-12.4-devel | 3:12.4.254.21-1.22.22.2.1.module_el8.10.0+4158+e796f37f · AlmaLinux:8 | Package registry (OSV) |
| almalinux:v8-13.6-devel | 3:13.6.233.17-1.24.14.1.2.module_el9.7.0+222+ef1c61e1 · AlmaLinux:9 | Package registry (OSV) |
| debian:node-undici | 7.24.5+dfsg+~cs3.2.0-1 · Debian:14 | Package registry (OSV) |
| npm:undici | 6.24.0 | Package registry (OSV) |
| npm:undici | 7.24.0 | Package registry (OSV) |
| red hat:nodejs | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs-debuginfo | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs-debugsource | 1:22.22.2-1.module+el8.10.0+24148+847b6786 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:nodejs-devel | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs-docs | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs-full-i18n | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs-libs | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs-libs-debuginfo | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs-npm | 1:10.9.7-1.22.22.2.1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs22 | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs22-debuginfo | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| red hat:nodejs22-debugsource | 1:22.22.2-1.el10_1 · Red Hat:enterprise_linux:10.1 | Package registry (OSV) |
| rocky linux:nodejs-nodemon | 0:3.0.1-1.module+el8.10.0+1666+930e28e8 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:nodejs-packaging | 0:2021.06-6.module+el8.10.0+40048+6d99f608 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:nodejs22 | 1:22.22.2-1.el10_1 · Rocky Linux:10 | Package registry (OSV) |
+1
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.
- Matteo Collinaremediation developer
- Rafael Gonzagaremediation reviewer
- Ethan Arrowoodremediation reviewer
- Aisle Researchreporter
- Ulises Gascónremediation reviewer
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-15280 days apartundici is vulnerable to Malicious WebSocket 64-bit length overflows undici parser and crashes the client30Monitor
- CVE-2026-19534176 days apartundici vulnerable to Denial of Service via unrequested WebSocket subprotocol30Monitor
- CVE-2026-85014176 days apartundici vulnerable to Denial of Service via WebSocketStream unclean close30Monitor
- CVE-2026-109869217 days apartundici vulnerable to Denial of Service via unhandled error on excessive content-encodings30Monitor
- CVE-2026-87018217 days apartundici vulnerable to Denial of Service via TLS 1.2 certificate-changing renegotiation30Monitor
- CVE-2026-87029217 days apartundici vulnerable to Denial of Service via unhandled exception in the decompress interceptor30Monitor
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.
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.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-248 · Uncaught ExceptionCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- datatracker.ietf.org/doc/html/rfc7692
- github.com/nodejs/undici/security/advisories/GHSA-v9p9-hfj2-hcw8
- hackerone.com/reports/3487486
- nodejs.org/api/zlib.html#class-zlibinflateraw
- access.redhat.com/errata/RHSA-2026:13826
- access.redhat.com/errata/RHSA-2026:17789
- access.redhat.com/errata/RHSA-2026:21772
- access.redhat.com/errata/RHSA-2026:21931
- access.redhat.com/errata/RHSA-2026:34342
- access.redhat.com/errata/RHSA-2026:56431
- access.redhat.com/errata/RHSA-2026:5807
- access.redhat.com/errata/RHSA-2026:7080
- access.redhat.com/errata/RHSA-2026:7123
- access.redhat.com/errata/RHSA-2026:7302
- access.redhat.com/errata/RHSA-2026:7310
- access.redhat.com/errata/RHSA-2026:7350
- access.redhat.com/errata/RHSA-2026:7670
- access.redhat.com/errata/RHSA-2026:7675
- access.redhat.com/errata/RHSA-2026:7983
Vendor advisories and official records. Exploit/PoC links are deliberately left out.