CVE-2019-12830
In MyBB before 1.8.21, an attacker can exploit a parsing flaw in the Private Message / Post renderer that leads to [video] BBCode persistent XSS to take over any forum account, aka a nested video MyCode issue.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.96%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In MyBB before 1.8.21, an attacker can exploit a parsing flaw in the Private Message / Post renderer that leads to [video] BBCode persistent XSS to take over any forum account, aka a nested video MyCode issue.
- CVSS 3.0
- 8.7 HIGHCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
- EPSS
- 0.96% probability · 62th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-79
- Affected
- mybb/mybb
- Source
- cve@mitre.org
EPSS 1.0% since 27 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-release/Release Notes, Third Party Advisory
- https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/Exploit, Vendor Advisory
- https://blog.mybb.com/2019/06/10/mybb-1-8-21-released-security-maintenance-release/Release Notes, Third Party Advisory
- https://blog.ripstech.com/2019/mybb-stored-xss-to-rce/Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.