Affects Commvault CommServe, a widely used enterprise backup platform; exploit can disrupt backups/service availability across organizations.
CVE-2026-77101
Stack-based buffer overflow in Commvault CommServe causing crashes and possible code execution.
Is CVE-2026-77101 being exploited?
Not confirmed. CVE-2026-77101 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 0.27% probability of exploitation in the next 30 days.
How severe is CVE-2026-77101?
CVE-2026-77101 is rated High with a CVSS score of 8.7. 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-2026-77101?
Yes. A fix has been recorded for CVE-2026-77101. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-77101 affect?
CVE-2026-77101 affects Commvault CommServe (backup server) on Windows/Linux. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-77101?
Apply Commvault maintenance release to CommServe immediately
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote stack buffer overflow allowing service crash (DoS) and potential remote code execution on CommServe servers.
Immediate action required
- affected>= 11.46.0 and <= 11.46.19
- affected>= 11.44.0 and <= 11.44.19
- affected>= 11.40.0 and <= 11.40.71
- affected>= 11.36.0 and <= 11.36.122
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.