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
Trending — 3 sources updated this week
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
52%
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 11× in last 7d / 70× 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 160 total refreshes for this CVE.

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

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 48.1% 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.

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