multipart is a fast multipart/form-data parser for python. Prior to 1.2.2, 1.3.1 and 1.4.0-dev, the parse_options_header() function in multipart.py uses a regular expression with an ambiguous alternation, which can cause exponential backtracking (ReDoS) when parsing maliciously crafted HTTP or multipart segment headers. This can be abused for denial of service (DoS) attacks against web applications using this library to parse request headers or multipart/form-data streams. The issue is fixed in 1.2.2, 1.3.1 and 1.4.0-dev.
CVE-2026-28356
“—” beside the score: it is equal to the CVSS score beside it.
This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 1.1% (64th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHmedium confidence
- EG Risk
- 49EG Risk 49/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity75% × 45%Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation1.1% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 1.1%
- EPSS %ILE
- 64th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
- EG Likelihood
- 1.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
March 12, 2026
Last Modified
August 24, 2026
Advisory Details (1)
Auto-updated Jun 12, 2026Denial of Service via maliciously crafted HTTP or multipart segment headers · Advisory · defnull/multipart · GitHub
https://github.com/defnull/multipart/security/advisories/GHSA-p2m9-wcp5-6qw3Vendor Advisories for CVE-2026-28356(7)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:73987Red Hat Product SecurityCritical
Red Hat Security Advisory: RHOAI 3.3.7 - Red Hat OpenShift AI
- RHSA-2026:42644Red Hat Product SecurityHigh
Red Hat Security Advisory: RHOAI 2.25.9 - Red Hat OpenShift AI
- RHSA-2026:37275Red Hat Product SecurityCritical
Red Hat Security Advisory: RHOAI 3.3.5 - Red Hat OpenShift AI
- RHSA-2026:10184Red Hat Product SecurityHigh
Red Hat Security Advisory: RHOAI 2.25.5 - Red Hat OpenShift AI
- RHSA-2026:6762Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Inference Server 3.2.2 (ROCm)
- RHSA-2026:6761Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Inference Server Model Optimization Tools 3.2.2 (CUDA)
- RHSA-2026:5809Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat AI Inference Server 3.2.2 (cuda-ubi9)
Patch Availability(8)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python3-multipart (1.3.0-3ubuntu0.1) @ resolute | 2026-10-17 | ubuntu |
| redhat | rhoai/odh-vllm-cpu-rhel9:1790274961 | 2026-09-30 | redhat |
| redhat | rhoai/odh-vllm-rocm-rhel9:1783998857 | 2026-07-21 | redhat |
| redhat | rhoai/odh-vllm-cpu-rhel9:1782996080 | 2026-07-09 | redhat |
| redhat | rhoai/odh-feature-server-rhel9:1776338381 | 2026-04-23 | redhat |
| redhat | rhaiis/model-opt-cuda-rhel9:1774547384 | 2026-04-07 | redhat |
| redhat | rhaiis/vllm-rocm-rhel9:1775252598 | 2026-04-07 | redhat |
| redhat | rhaiis/vllm-cuda-rhel9:1774351144 | 2026-03-25 | redhat |
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
(3 across 3 ecosystems)
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| multipart | 1.2.1-2 |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| multipart | 1.2.1-2, 1.3.0-1, 1.3.0-2, 1.3.0-3 |
| — |
PyPI(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| multipart | 0.1 ... 1.3.0 (13 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(1)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 10× in last 7d / 32× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 95 of 241 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 5 repeat rows among the latest 100 are merged into the row they repeat. The 146 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-21 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-20 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-19 16:31 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-18 16:31 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-18 03:50 UTCEG score recompute
- 2026-10-17 16:33 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-17 16:17 UTCEG score recompute
- 2026-10-17 16:17 UTCVendor advisory
- 2026-10-16 16:41 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-15 16:31 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-14 16:32 UTCEPSS rescoreEPSS 1.1% · 64th percentile
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-10-12 16:16 UTCEG score recompute
- 2026-10-11 19:59 UTCEG score recompute
- 2026-10-11 17:12 UTCEG score recompute
- 2026-10-11 14:42 UTCEG score recompute
- 2026-10-11 13:48 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.1% · 63rd percentile
- 2026-10-08 17:11 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-07 23:47 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-06 15:17 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-05 17:42 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-04 23:21 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
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- 2026-10-03 14:25 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-01 19:49 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-10-01 07:40 UTCOSV refresh
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-26 00:26 UTCEPSS rescoreEPSS 1.0% · 62nd percentile
- 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-09-18 19:27 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-09-17 19:30 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-12 08:23 UTCOSV refresh
- 2026-09-11 14:52 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-02 14:11 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-01 13:53 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-09-01 04:39 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-24 14:17 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-24 13:32 UTCEG score recompute
- 2026-08-24 13:32 UTCVendor advisory
- 2026-08-24 12:27 UTCEG score recompute
- 2026-08-24 12:27 UTCVendor advisory
- 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.7% · 51st percentile
- 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-16 11:43 UTCEG score recompute
- 2026-08-16 11:43 UTCVendor advisory
- 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-14 20:05 UTCVendor advisory
- 2026-08-14 07:43 UTCEG score recompute
- 2026-08-14 07:43 UTCVendor advisory
- 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-12 22:47 UTCEG score recompute
- 2026-08-12 22:47 UTCVendor advisory
- 2026-08-12 13:50 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-11 21:43 UTCEG score recompute
- 2026-08-11 21:43 UTCVendor advisory
- 2026-08-11 13:42 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-11 04:51 UTCEG score recompute
- 2026-08-11 04:51 UTCVendor advisory
- 2026-08-11 00:00 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-10 06:38 UTCVendor advisory
- 2026-08-09 18:57 UTCEG score recompute
- 2026-08-09 18:57 UTCVendor advisory
- 2026-08-09 13:46 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-09 07:24 UTCEG score recompute
- 2026-08-09 07:24 UTCVendor advisory
- 2026-08-08 16:37 UTCEPSS rescoreEPSS 0.7% · 50th percentile
- 2026-08-08 05:39 UTCVendor advisory
- 2026-08-07 18:06 UTCEG score recompute
- 2026-08-07 18:06 UTCVendor advisory
- 2026-08-06 19:49 UTCEG score recompute
Related CVEs(same vendor + same CWE)
Same vendor
10 shownredhat:RHSA-2026:10184 · redhat:RHSA-2026:42644 · redhat:RHSA-2026:37275
Frequently asked(5)
What is CVE-2026-28356?
When was the CVE record for CVE-2026-28356 published?
Is CVE-2026-28356 actively exploited?
What is the CVSS score of CVE-2026-28356?
How do I remediate CVE-2026-28356?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-28356
Is Your Infrastructure Affected by CVE-2026-28356?
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