CVE-2026-93647
An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address
- Risk score
- 63/100
- CVSS
- 9.3 v3.1
- Exploit chance (30 days)
- 0.2%
- Published
- 25 Sep 2026
Open in the live forecast Today's forecast
What to know
- What it is
- An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address. Selecting the message in Zimbra Classic triggers stored XSS, allowing the attacker to access mailbox data and act as the victim.
- Affected
- See advisory
- Fix
- Apply the vendor's security update; see the linked advisory.
- Exploitation
- No known exploitation
Why it is Amber
- CVSS 9.3 critical
- Remotely exploitable without logging in
References
Original description
An unauthenticated calendar sender can place active markup in a COUNTER message's RFC From address. Selecting the message in Zimbra Classic triggers stored XSS, allowing the attacker to access mailbox data and act as the victim.
Last activity 25 Sep 2026. Patch Forecast updates every hour.