CVE-2026-42259
CVE-2026-42259 is a medium-severity vulnerability with a CVSS 4.0 base score of 5.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-601.
Key facts
- Severity: Medium (CVSS 4.0 base score 5.1)
- EPSS exploit prediction: 0% (26th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-28431
- Weakness: CWE-601
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-42259?
- 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.
- How severe is CVE-2026-42259?
- CVE-2026-42259 has a CVSS 4.0 base score of 5.1, rated medium severity.
- Is CVE-2026-42259 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-42259?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-42259 have an EU (EUVD) identifier?
- Yes. CVE-2026-42259 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28431.
- When was CVE-2026-42259 published?
- CVE-2026-42259 was published on 2026-05-07 and last updated on 2026-06-17.
References
Other CWE-601 (Open Redirect) vulnerabilities
- CVE-2018-3774 — Critical (CVSS 10.0): Incorrect parsing in url-parse <1.4.3 returns wrong hostname which leads to multiple vulnerabilities such as SSRF, Open…
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- CVE-2024-22891 — Critical (CVSS 9.8): Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link.