VulnerabilityDeferred

CVE-2026-42259

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…

MEDIUM 5.1EPSS 0.34%

Does this matter?

Lower severity and a low EPSS score (0.34%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0: 5.1 MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS: 0.34% probability · 27th percentile
CISA KEV: Not listed
Weakness: CWE-601
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.