CVE-2026-100698

MEDIUMCVSS 5.8/10EPSS 0.28%

Last modified

CVE-2026-100698 is a medium-severity vulnerability rated 5.8/10 on the CVSS scale. Adminer 5.5.1 through 6.0.1 improperly parses the login 'server' string in the host_port() function in adminer/include/functions.inc.php. The port capture group requires pure digits anchored to the end of the string, so any server value with a non-digit tail fails the regex and falls back to returning the whole string as the host with an empty port. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

Adminer 5.5.1 through 6.0.1 improperly parses the login 'server' string in the host_port() function in adminer/include/functions.inc.php. The port capture group requires pure digits anchored to the end of the string, so any server value with a non-digit tail fails the regex and falls back to returning the whole string as the host with an empty port. Because the privileged-port restriction in adminer/include/auth.inc.php inspects only the parsed port, the check is skipped, and the mysqli/mysqlnd client subsequently re-parses host:port from the host string and opens a TCP connection. A remote, unauthenticated attacker who can reach the Adminer login page can submit a crafted value such as 127.0.0.1:80/x to make the server initiate TCP connections to arbitrary internal hosts and privileged ports before credentials are validated, enabling server-side request forgery and blind internal port scanning (connection refused vs. handshake vs. timeout acts as a liveness oracle). This is a regression that re-opens the bypass fixed in 5.5.0 (GHSA-58cq-mgw2-38m5). Fixed in 6.0.2.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
vranaadminer< 6.0.2

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-100698?
Adminer 5.5.1 through 6.0.1 improperly parses the login 'server' string in the host_port() function in adminer/include/functions.inc.php. The port capture group requires pure digits anchored to the end of the string, so any server value with a non-digit tail fails the regex and falls back to returning the whole string as the host with an empty port. Because the privileged-port restriction in adminer/include/auth.inc.php inspects only the parsed port, the check is skipped, and the mysqli/mysqlnd client subsequently re-parses host:port from the host string and opens a TCP connection. A remote, unauthenticated attacker who can reach the Adminer login page can submit a crafted value such as 127.0.0.1:80/x to make the server initiate TCP connections to arbitrary internal hosts and privileged ports before credentials are validated, enabling server-side request forgery and blind internal port scanning (connection refused vs. handshake vs. timeout acts as a liveness oracle). This is a regression that re-opens the bypass fixed in 5.5.0 (GHSA-58cq-mgw2-38m5). Fixed in 6.0.2.
How severe is CVE-2026-100698?
CVE-2026-100698 has a CVSS score of 5.8/10 (MEDIUM severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.
How do I fix CVE-2026-100698?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST