CVE-2026-42874Microdot: HTTP response splitting in Response.set_cookie()
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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Microdot is a minimalistic Python web framework. Prior to 2.6.1, the Response.set_cookie() method does not sanitize its string arguments, and in particular will not detect the presence of the \r\n sequence in them. This can be a potential source of header injection attacks. For a header injection attack through this issue to be possible, an attacker must first infiltrate the client (for example through an independent XSS attack), so that it can send malicious information that is destined to be stored in a cookie by the server on behalf of the victim. An attacker that infiltrates one client can only orchestrate a header injection attack for that client, all other clients that were not infiltrated are safe. This vulnerability is fixed in 2.6.1.
- CVSS
- 3.7 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weakness (CWE)
- CWE-113
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- May 13, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
miguelgrinberg microdot miguelgrinberg:microdot (from the name) | before 2.6.1 | CNA record |
References
- https://github.com/miguelgrinberg/microdot/security/advisories/GHSA-7wc8-wvc4-m498x-refsource-confirm
- https://github.com/miguelgrinberg/microdot/commit/99b281b45faef8472410f2d56bfef496dfbd95d5x-refsource-misc
- https://github.com/miguelgrinberg/microdot/blob/main/CHANGES.mdx-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.