CVE-2026-23829

MEDIUMNVD 5.35.3
EchelonGraph scoreLOW confidence

This medium-severity CVE scores 5.3 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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).

Triggered by: NVD CVSS baseline
Sources: nvd
Elevated
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 5.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing ones) by including carriage return characters (\r) in the email address. This header injection occurs because the regex intended to filter control characters fails to exclude \r and \n when used inside a character class. Version 1.28.3 fixes this issue.

CVSS v3
5.3
EG Score
5.3(low)
EPSS
70.4%
KEV
Not listed

Published

January 19, 2026

Last Modified

February 23, 2026

References (3)

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/axllent/mailpit—1.28.3—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 48× 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.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
  4. 2026-07-20 17:08 UTCEPSS rescore
  5. 2026-07-19 14:31 UTCEPSS rescore
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  7. 2026-07-19 02:29 UTCEPSS rescore
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  9. 2026-07-18 10:04 UTCEPSS rescore
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  11. 2026-07-16 17:03 UTCEPSS rescore
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  15. 2026-07-15 02:00 UTCEPSS rescore
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  17. 2026-07-13 22:30 UTCEPSS rescore
  18. 2026-07-13 06:13 UTCEPSS rescore
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  20. 2026-07-12 05:46 UTCEPSS rescore
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  22. 2026-07-11 08:27 UTCEPSS rescore
  23. 2026-07-09 19:10 UTCEPSS rescore
  24. 2026-07-08 15:15 UTCEPSS rescore
  25. 2026-07-08 15:15 UTCEPSS rescore
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  1. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 05:02 UTCOSV refresh
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 02:30 UTCEPSS rescore
  7. 2026-07-04 06:31 UTCEPSS rescore
  8. 2026-07-04 06:31 UTCEPSS rescore
  9. 2026-07-01 15:06 UTCEPSS rescore
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  11. 2026-06-30 23:22 UTCEPSS rescore
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  13. 2026-06-28 14:07 UTCEPSS rescore
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  15. 2026-06-28 04:56 UTCEPSS rescore
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  17. 2026-06-27 03:08 UTCEPSS rescore
  18. 2026-06-25 13:49 UTCEPSS rescore
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  20. 2026-06-24 14:05 UTCEPSS rescore
  21. 2026-06-24 14:05 UTCEPSS rescore
  22. 2026-06-23 21:33 UTCEPSS rescore
  23. 2026-06-23 21:32 UTCEPSS rescore
  24. 2026-06-22 14:25 UTCEPSS rescore
  25. 2026-06-22 14:25 UTCEPSS rescore
  26. 2026-06-21 14:56 UTCEPSS rescore
  27. 2026-06-21 14:56 UTCEPSS rescore
  28. 2026-06-21 01:59 UTCEPSS rescore
  29. 2026-06-21 01:59 UTCEPSS rescore
  30. 2026-06-19 19:25 UTCEPSS rescore
  31. 2026-06-19 19:25 UTCEPSS rescore
  32. 2026-06-18 17:52 UTCEPSS rescore
  33. 2026-06-17 17:53 UTCEPSS rescore
  34. 2026-06-17 17:53 UTCEPSS rescore
  35. 2026-06-17 16:13 UTCOSV refresh
  36. 2026-06-16 17:52 UTCEPSS rescore
  37. 2026-06-15 17:48 UTCEPSS rescore
  38. 2026-06-14 23:18 UTCEPSS rescore
  39. 2026-06-13 23:00 UTCEPSS rescore
  40. 2026-06-12 23:12 UTCEPSS rescore
  41. 2026-06-12 23:12 UTCEPSS rescore
  42. 2026-06-11 14:00 UTCEPSS rescore
  43. 2026-06-10 22:18 UTCEPSS rescore
  44. 2026-06-10 22:18 UTCEPSS rescore
  45. 2026-06-10 13:22 UTCEPSS rescore
  46. 2026-06-08 14:17 UTCEPSS rescore
  47. 2026-06-08 14:17 UTCEPSS rescore
  48. 2026-06-07 15:25 UTCEPSS rescore
  49. 2026-06-07 15:24 UTCEPSS rescore
  50. 2026-06-05 22:47 UTCEPSS rescore
  51. 2026-06-05 06:10 UTCEPSS rescore
  52. 2026-06-05 06:10 UTCEPSS rescore
  53. 2026-06-04 13:12 UTCEPSS rescore
  54. 2026-06-04 13:12 UTCEPSS rescore
  55. 2026-06-04 13:12 UTCEPSS rescore
  56. 2026-06-02 20:13 UTCEPSS rescore
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  58. 2026-06-01 13:51 UTCEPSS rescore
  59. 2026-06-01 13:51 UTCEPSS rescore
  60. 2026-06-01 13:51 UTCEPSS rescore
  61. 2026-05-31 22:30 UTCEPSS rescore
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  63. 2026-05-31 00:16 UTCEPSS rescore
  64. 2026-05-31 00:16 UTCEPSS rescore
  65. 2026-05-31 00:16 UTCEPSS rescore
  66. 2026-05-29 13:44 UTCEPSS rescore
  67. 2026-05-29 13:44 UTCEPSS rescore
  68. 2026-05-29 13:40 UTCEG score recompute

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleinetwork/cves/2026/CVE-2026-23829.yaml
    First seen Jan 1, 2026

    Mailpit < 1.28.2 - SMTP CRLF Injection

    Open source ↗

Frequently asked(5)

What is CVE-2026-23829?
CVE-2026-23829 is a medium vulnerability published on January 19, 2026. Mailpit is an email testing tool and API for developers. Prior to version 1.28.3, Mailpit's SMTP server is vulnerable to Header Injection due to an insufficient Regular Expression used to validate RCPT TO and MAIL FROM addresses. An attacker can inject arbitrary SMTP headers (or corrupt existing…
When was CVE-2026-23829 disclosed?
CVE-2026-23829 was first published in the National Vulnerability Database on January 19, 2026, with the most recent update on February 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23829 actively exploited?
CVE-2026-23829 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 70.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-23829?
CVE-2026-23829 has a CVSS v3 base score of 5.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-23829?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23829, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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