Vulnerability in Vrana Adminer
CVE-2026-63771
Adminer before 5.4.3 contains a cookie injection vulnerability that allows attackers to manipulate cookie attributes by injecting arbitrary values through the unsanitized X-Forwarded-Prefix HTTP header used in Set-Cookie path attributes. Attackers can exploit a misconfigured reverse proxy to downgrade SameSite protection and enable cross-origin authenticated requests, bypassing cookie security controls.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (36.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Vrana Adminer — versions 0
Weakness classification (CWE)
References
- github.com/vrana/adminer/issues/1298 (issue-tracking, technical-description, exploit)
- github.com/vrana/adminer/releases (release-notes)
- github.com/vrana/adminer/security/advisories/GHSA-c533-9qwm-8w5h (vendor-advisory)
- www.vulncheck.com/advisories/adminer-cookie-injection-via-x-forwarded-prefix-he… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-63771?
- CVE-2026-63771 is a high-severity vulnerability in Vrana Adminer, classified under HTTP Response Splitting. CVSS score: 7.1/10. Published 2026-07-20.
- How severe is CVE-2026-63771?
- High severity. CVSS v3 base score is 7.1 out of 10.