CVE-2026-27947
Authenticated RCE in Group-Office via winmail.dat TNEF parsing.
Is CVE-2026-27947 being exploited?
Not confirmed. CVE-2026-27947 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 0.73% probability of exploitation in the next 30 days.
How severe is CVE-2026-27947?
CVE-2026-27947 is rated Critical with a CVSS score of 9.4. 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-2026-27947?
Yes. A fix has been recorded for CVE-2026-27947. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-27947 affect?
CVE-2026-27947 affects Group-Office < 26.0.9, Group-Office < 25.0.87, Group-Office < 6.8.154. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-27947?
Update to patched versions (>=26.0.9 / >=25.0.87 / >=6.8.154).
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated remote code execution via TNEF parsing; attacker-controlled filenames enable arbitrary commands.
Patch when possible
- affected>= 26.0.0 and < 26.0.9
- affected>= 25.0.0 and < 25.0.87
- affected< 6.8.154
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.