Actively exploited vulnerability
Adminer: server-side request forgery flaw under attack
CVE-2021-21311 · Adminer Server-Side Request Forgery Vulnerability
What is affected
Adminer is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.
Adminer contains a server-side request forgery vulnerability that, when exploited, allows a remote attacker to obtain potentially sensitive information.
What an attacker can do
This is a server-side request forgery flaw. It lets an attacker make the server send requests on their behalf and reach internal systems that are not exposed to the internet.
- How it is reached
- Over the internet or network
- Access the attacker needs
- No account needed
- Does the victim have to do something?
- No, works without the victim doing anything
What to do
- At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
- If you administer Adminer at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
- If the product is past its support date and no fix exists, take it off the internet or retire it.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vendor advisories and fixes
- github.comgithub.com/vrana/adminer/security/advisories/GHSA-x5r2-hj5c-8jx6
How urgent is it
CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on September 29, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by October 20, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.
The EPSS model estimates a 98% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99.9% of all scored vulnerabilities.
Its CVSS severity score is 7.2 out of 10 (high), as recorded in the US National Vulnerability Database.
Technical description
Adminer is an open-source database management in a single PHP file. In adminer from version 4.0.0 and before 4.7.9 there is a server-side request forgery vulnerability. Users of Adminer versions bundling all drivers (e.g. `adminer.php`) are affected. This is fixed in version 4.7.9.