CVE-2026-42561

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.7%, top 48% 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).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: None knownExposed: 0

A fix is available — apply it.

Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual part header. An attacker could send a request with either many repeated headers without terminating the header block or a single very large header value, causing excessive CPU work before request rejection or completion. This vulnerability is fixed in 0.0.27.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
53%
KEV
Not listed

Published

May 13, 2026

Last Modified

August 7, 2026

Advisory Details (1)

Auto-updated May 13, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

Denial of Service via unbounded multipart part headers · Advisory · Kludex/python-multipart · GitHub

https://github.com/Kludex/python-multipart/security/advisories/GHSA-pp6c-gr5w-3c5g

Vendor Advisories for CVE-2026-42561(8)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(8)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatsatellite/iop-vulnerability-engine-rhel9:17858065542026-08-06redhat
redhatsatellite/iop-vulnerability-engine-rhel9:17845541232026-08-06redhat
redhatsatellite/iop-vmaas-rhel9:17859299942026-08-06redhat
redhatsatellite/iop-advisor-engine-rhel9:17848344022026-07-23redhat
redhatmta/mta-solution-server-rhel9:17841098832026-07-21redhat
redhatansible-automation-platform-26/mcp-tools-rhel9:17839206402026-07-20redhat
redhatansible-automation-platform-27/mcp-tools-rhel9:17839184032026-07-20redhat
redhatrhoai/odh-mlserver-rhel9:17828878482026-07-09redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
python-multipart0.0.17-1 ... 0.0.9-1 (14 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
python-multipart0.0.17-1 ... 0.0.9-1 (13 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
python-multipart0.0.20-1, 0.0.20-1.1, 0.0.20-1.1~deb13u1, 0.0.22-1, 0.0.26-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
python-multipart0.0.20-1, 0.0.20-1.1, 0.0.20-1.1~deb13u1, 0.0.22-1, 0.0.26-1——
PyPI(1)
PackageVulnerable rangeFixed inDependents
python-multipart0.0.1 ... 0.0.9 (26 versions)0.0.27—

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 31× 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.

Showing the most recent 100 of 181 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-17 19:31 UTCEPSS rescore
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-13 16:47 UTCEPSS rescore
  6. 2026-09-12 15:01 UTCEPSS rescore
  7. 2026-09-11 14:53 UTCEPSS rescore
  8. 2026-09-11 09:37 UTCEPSS rescore
  9. 2026-09-11 08:23 UTCOSV refresh
  10. 2026-09-10 09:34 UTCEPSS rescore
  11. 2026-09-08 22:00 UTCEPSS rescore
  12. 2026-09-07 16:01 UTCEPSS rescore
  13. 2026-09-06 13:47 UTCEPSS rescore
  14. 2026-09-04 05:06 UTCEPSS rescore
  15. 2026-09-02 14:12 UTCEPSS rescore
  16. 2026-09-01 13:54 UTCEPSS rescore
  17. 2026-08-30 19:17 UTCEPSS rescore
  18. 2026-08-30 01:22 UTCEPSS rescore
  19. 2026-08-28 21:41 UTCEPSS rescore
  20. 2026-08-27 14:25 UTCEPSS rescore
  21. 2026-08-26 14:46 UTCEPSS rescore
  22. 2026-08-25 13:49 UTCEPSS rescore
  23. 2026-08-23 17:49 UTCEG score recompute
  24. 2026-08-23 17:49 UTCVendor advisory
  25. 2026-08-23 00:19 UTCEPSS rescore
Show 75 more
  1. 2026-08-22 02:03 UTCEG score recompute
  2. 2026-08-22 02:03 UTCVendor advisory
  3. 2026-08-21 23:49 UTCEPSS rescore
  4. 2026-08-20 22:55 UTCEPSS rescore
  5. 2026-08-20 19:46 UTCEG score recompute
  6. 2026-08-20 19:46 UTCVendor advisory
  7. 2026-08-19 17:03 UTCEPSS rescore
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-17 13:47 UTCEPSS rescore
  10. 2026-08-17 10:29 UTCEG score recompute
  11. 2026-08-17 10:29 UTCVendor advisory
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 04:01 UTCEG score recompute
  14. 2026-08-16 04:01 UTCVendor advisory
  15. 2026-08-16 02:14 UTCEPSS rescore
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-14 15:33 UTCVendor advisory
  18. 2026-08-14 02:29 UTCEG score recompute
  19. 2026-08-14 02:29 UTCVendor advisory
  20. 2026-08-13 22:00 UTCEPSS rescore
  21. 2026-08-13 04:53 UTCVendor advisory
  22. 2026-08-12 15:48 UTCEG score recompute
  23. 2026-08-12 15:48 UTCVendor advisory
  24. 2026-08-12 13:51 UTCEPSS rescore
  25. 2026-08-11 15:27 UTCEG score recompute
  26. 2026-08-11 15:27 UTCVendor advisory
  27. 2026-08-11 13:43 UTCEPSS rescore
  28. 2026-08-11 00:55 UTCEG score recompute
  29. 2026-08-11 00:55 UTCVendor advisory
  30. 2026-08-11 00:00 UTCEPSS rescore
  31. 2026-08-10 04:01 UTCVendor advisory
  32. 2026-08-09 14:57 UTCEG score recompute
  33. 2026-08-09 14:57 UTCVendor advisory
  34. 2026-08-09 13:46 UTCEPSS rescore
  35. 2026-08-09 01:53 UTCEG score recompute
  36. 2026-08-09 01:53 UTCVendor advisory
  37. 2026-08-08 16:37 UTCEPSS rescore
  38. 2026-08-08 01:30 UTCEG score recompute
  39. 2026-08-08 01:30 UTCVendor advisory
  40. 2026-08-07 12:25 UTCEG score recompute
  41. 2026-08-07 12:25 UTCVendor advisory
  42. 2026-08-07 12:08 UTCEG score recompute
  43. 2026-08-07 12:08 UTCVendor advisory
  44. 2026-08-07 01:22 UTCEG score recompute
  45. 2026-08-07 01:22 UTCVendor advisory
  46. 2026-08-06 13:46 UTCEPSS rescore
  47. 2026-08-06 10:44 UTCVendor advisory
  48. 2026-08-05 21:40 UTCEG score recompute
  49. 2026-08-05 21:40 UTCVendor advisory
  50. 2026-08-05 19:17 UTCEPSS rescore
  51. 2026-08-04 15:10 UTCEPSS rescore
  52. 2026-08-04 10:38 UTCEPSS rescore
  53. 2026-08-03 19:07 UTCEG score recompute
  54. 2026-08-03 19:07 UTCVendor advisory
  55. 2026-08-03 10:36 UTCEPSS rescore
  56. 2026-08-02 22:26 UTCVendor advisory
  57. 2026-08-02 09:21 UTCEG score recompute
  58. 2026-08-02 09:21 UTCVendor advisory
  59. 2026-08-02 02:27 UTCEPSS rescore
  60. 2026-08-01 19:35 UTCEG score recompute
  61. 2026-08-01 19:35 UTCVendor advisory
  62. 2026-08-01 04:16 UTCEPSS rescore
  63. 2026-07-30 16:28 UTCEPSS rescore
  64. 2026-07-30 01:30 UTCEPSS rescore
  65. 2026-07-28 15:36 UTCEPSS rescore
  66. 2026-07-27 14:13 UTCEPSS rescore
  67. 2026-07-26 14:54 UTCEPSS rescore
  68. 2026-07-26 14:54 UTCEPSS rescore
  69. 2026-07-26 08:21 UTCEG score recompute
  70. 2026-07-26 08:21 UTCVendor advisory
  71. 2026-07-25 14:18 UTCEPSS rescore
  72. 2026-07-24 14:17 UTCEPSS rescore
  73. 2026-07-23 14:18 UTCEPSS rescore
  74. 2026-07-23 03:11 UTCEG score recompute
  75. 2026-07-22 14:08 UTCEPSS rescore

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-42561?
CVE-2026-42561 is a high vulnerability published on May 13, 2026. Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.27, python-multipart has a denial of service vulnerability in multipart part header parsing. When parsing multipart/form-data, MultipartParser previously had no limit on the number of part headers or the size of an individual…
When was CVE-2026-42561 disclosed?
CVE-2026-42561 was first published in the National Vulnerability Database on May 13, 2026, with the most recent update on August 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42561 actively exploited?
CVE-2026-42561 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 46.9% of all scored CVEs.
What is the CVSS score of CVE-2026-42561?
CVE-2026-42561 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-42561?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42561, 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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