Web
CVE-2026-88804
Unauthenticated stored XSS in Rancher UI enabling remote script execution
Major vulnerability. Rancher is widely used to manage Kubernetes clusters; an unauthenticated UI XSS can lead to session theft and compromise of cluster management.
- CVSS
- 9.6Criticalscored by the publisher (CNA)
- Exploited in the wild
- Not knownUnvetted proof-of-concept code on GitHub; not in CISA KEV
- EPSS
- 1.0%chance of exploitation in the next 30 daystop 36% of scored CVEsFIRST score of 12 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 28 Sept 2026analysed here 29 Sept 2026
Summary
Impact
Unauthenticated stored XSS; attackers can run JS in admin/user browsers, steal sessions, perform CSRF, and potentially compromise cluster management.
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| SUSE Rancher | >= 2.15.0 and < 2.15.2>= 2.14.0 and < 2.14.6>= 2.13.0 and < 2.13.10>= 2.12.0 and < 2.12.14>= 2.11.0se and < 2.11.18Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- SUSE Rancher 2.15 (<2.15.2)
- SUSE Rancher 2.14 (<2.14.6)
- SUSE Rancher 2.13 (<2.13.10)
- SUSE Rancher 2.12 (<2.12.14)
- SUSE Rancher 2.11 (<2.11.18)
Fix and mitigation
Action required
Immediate action required
WAF and other mitigations
Can a WAF block it? Yes. The vulnerability is an unauthenticated stored cross-site scripting (XSS) in the Rancher web interface, meaning malicious scripts are stored via HTTP requests and later executed in users' browsers. A WAF can partly detect such attacks by matching suspicious script tags or event handlers in input fields, but some legitimate inputs might resemble these patterns. A custom WAF rule can filter stored script tags or event handlers in UI input fields, but attackers can vary the request. No tracked WAF vendor has published a rule for this CVE yet.
What a custom rule would match: stored script tags or event handlers in UI input fields
Also consider: patch · custom WAF rule · CSP · output encoding
Based on an AI reading of the CVE description, and no vendor rule found yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Not listed as of our last sync.
- Public exploit code
- Unvetted proof-of-concept code on GitHub: 1 GitHub proof of concept
- CISA SSVC
- exploitation none, automatable no, technical impact totalAssessed by CISA 28 Sept 2026 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
GitHub proofs of concept
- R0gfall/CVE-2026-888041 stars
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 28 Sept 2026Published
- 28 Sept 2026CISA SSVC assessment: exploitation nonesame day later
- 28 Sept 2026CVE record last updatedsame day later
- 29 Sept 2026Analysed by vulneraibility.com1 day later
- 29 Oct 2026First proof-of-concept repository on GitHub (unvetted)29 days later
Common questions
Is CVE-2026-88804 being exploited?
Not confirmed. CVE-2026-88804 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 1.0% probability of exploitation in the next 30 days.
How severe is CVE-2026-88804?
CVE-2026-88804 is rated Critical with a CVSS score of 9.6. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-88804?
Yes. A fix has been recorded for CVE-2026-88804. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-88804 affect?
CVE-2026-88804 affects SUSE Rancher 2.15 (<2.15.2), SUSE Rancher 2.14 (<2.14.6), SUSE Rancher 2.13 (<2.13.10), SUSE Rancher 2.12 (<2.12.14), and 1 further product or version. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-88804?
Upgrade to patched versions, restrict UI exposure, and rotate sessions/credentials.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
1 reference in the CVE record, grouped by the tags the record gives them.
Advisories (1)
- github.com /rancher/rancher/security/advisories/GHSA-992f-xh8r-jg2f
Also tracked as GHSA-992f-xh8r-jg2f (OSV).
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
- OSV: advisory aliases and downstream package versions
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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