Vulnerability · Published May 7, 2026 · Assigned by GitHub_M

CVE-2026-42259Saltcorn: Open Redirect in `POST /auth/login` due to incomplete `is_relative_url` validation (backslash bypass)

Medium 5.1

In plain English

A medium-severity open redirect in saltcorn from saltcorn. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)5.1Medium

Exploit odds (30 days)0.3%top 72.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

Saltcorn is an extensible, open source, no-code database application builder. Prior to versions 1.4.6, 1.5.6, and 1.6.0-beta.5, Saltcorn validates the post-login dest parameter with a string check that only blocks :/ and //. Because all WHATWG-compliant browsers normalise backslashes (\) to forward slashes (/) for special schemes, a payload such as /\evil.com/path slips through is_relative_url(), is emitted unchanged in the HTTP Location header, and causes the browser to navigate cross-origin to an attacker-controlled domain. The bug is reachable on a default install and only requires a victim who can be tricked into logging in via a crafted Saltcorn URL. This issue has been patched in versions 1.4.6, 1.5.6, and 1.6.0-beta.5.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	@saltcorn/server	1.4.6	GHSA-f3g8-9xv5-77gv
npm	@saltcorn/server	1.5.6	GHSA-f3g8-9xv5-77gv
npm	@saltcorn/server	1.6.0-beta.5	GHSA-f3g8-9xv5-77gv

Affected products (as reported)

Vendor	Product	Versions
saltcorn	saltcorn	< 1.4.6>= 1.5.0-beta.0, < 1.5.6>= 1.6.0-alpha.0, < 1.6.0-beta.5

Weakness: CWE-601 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

References

https://github.com/saltcorn/saltcorn/security/advisories/GHSA-f3g8-9xv5-77gv x_refsource_CONFIRM