CVE-2026-39429
Auth bypass: root shard cache server exposed; read/write before fixes.
Is CVE-2026-39429 being exploited?
Not confirmed. CVE-2026-39429 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 0.44% probability of exploitation in the next 30 days.
How severe is CVE-2026-39429?
CVE-2026-39429 is rated High with a CVSS score of 8.2. 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-2026-39429?
Yes. A fix has been recorded for CVE-2026-39429. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-39429 affect?
CVE-2026-39429 affects kcp project - root shard cache server (pre-0.29.3/0.30.3). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-39429?
Upgrade to 0.30.3/0.29.3+, enable auth, and limit root shard exposure.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated access to cache enables read/write data, risk of tampering, exfiltration, or control-plane disruption.
Patch when possible
- affected>= 0.30.0 and < 0.30.3
- affected< 0.29.3
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.