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.
CVE-2026-42874
This low-severity CVE scores 3.7 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 88% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 3.7
- EG Score
- 3.7(medium)
- EPSS
- 11.9%
- KEV
- Not listed
Published
May 11, 2026
Last Modified
May 13, 2026
References (3)
- security-advisories@githubhttps://github.com/miguelgrinberg/microdot/blob/main/CHANGES.md
- security-advisories@githubhttps://github.com/miguelgrinberg/microdot/commit/99b281b45faef8472410f2d56bfef496dfbd95d5
- security-advisories@githubhttps://github.com/miguelgrinberg/microdot/security/advisories/GHSA-7wc8-wvc4-m498
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| microdot | 0.1.0 ... 2.6.0 (48 versions) | 2.6.1 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 36× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
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- 2026-06-28 04:56 UTCEPSS rescore
- 2026-06-27 03:08 UTCEPSS rescore
- 2026-06-26 04:48 UTCEG score recompute
- 2026-06-25 13:49 UTCEPSS rescore
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- 2026-06-23 21:33 UTCEPSS rescore
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- 2026-06-21 14:56 UTCEPSS rescore
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- 2026-06-19 19:25 UTCEPSS rescore
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- 2026-06-16 11:57 UTCEG score recompute
- 2026-06-15 17:49 UTCEPSS rescore
- 2026-06-13 23:00 UTCEPSS rescore
- 2026-06-13 08:21 UTCEG score recompute
- 2026-06-12 23:12 UTCEPSS rescore
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- 2026-06-10 07:58 UTCEG score recompute
- 2026-06-08 14:17 UTCEPSS rescore
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- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 15:25 UTCEPSS rescore
- 2026-06-07 07:35 UTCEG score recompute
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-06 13:47 UTCEPSS rescore
- 2026-06-05 22:47 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-05 06:10 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-04 13:12 UTCEPSS rescore
- 2026-06-04 07:16 UTCEG score recompute
- 2026-06-02 20:13 UTCEPSS rescore
- 2026-06-01 13:52 UTCEPSS rescore
- 2026-06-01 13:52 UTCEPSS rescore
- 2026-06-01 06:56 UTCEG score recompute
- 2026-05-31 22:30 UTCEPSS rescore
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- 2026-05-29 13:44 UTCEPSS rescore
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- 2026-05-27 13:40 UTCEPSS rescore
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- 2026-05-26 13:44 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-26 07:18 UTCEPSS rescore
- 2026-05-23 00:07 UTCEG score recompute
- 2026-05-20 22:38 UTCEPSS rescore
- 2026-05-20 22:38 UTCEPSS rescore
- 2026-05-20 13:12 UTCEG score recompute
- 2026-05-20 11:22 UTCEPSS rescore
- 2026-05-20 11:22 UTCEPSS rescore
Frequently asked(5)
What is CVE-2026-42874?
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