Low severity · published Jan 20, 2026
CVE-2026-21640
HackerOne community member Faraz Ahmed (PakCyberbot) has reported a format string injection in the Revive Adserver settings
2.7
CVSS
0.3%
EPSS
No
On KEV
Description
HackerOne community member Faraz Ahmed (PakCyberbot) has reported a format string injection in the Revive Adserver settings. When specific character combinations are used in a setting, the admin user console could be disabled due to a fatal PHP error.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 16% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RA
Revive Adserver · Revive
6 through 6.0.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-21640
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-21640
Third Party Advisory
https://hackerone.com/reports/3445332
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