CVE-2026-28356
No exploitation reported by the sources we read.
- Published2026-03-12
- Fixed in1.3.1 · 1.2.2
- WeaknessCWE-1333
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
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.
Timeline
dates in UTC- 2026-03-1217:16CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-28356?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-28356?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.3 | ≥ 1.3.0, < 1.3.1 | 1.3.1 | OSV |
| 1.2 | < 1.2.2 | 1.2.2 | OSV |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
Red Hat Security Advisory: RHOAI 3.3.5 - Red Hat OpenShift AI
Red Hat Security Advisory: RHOAI 2.25.5 - Red Hat OpenShift AI
Fix
- Update multipart to 1.3.1 · 1.2.2
- Vendor fix Red Hat Product Security RHSA-2026:37275 · 2 productsFor Red Hat OpenShift AI 3.3.5 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
- Vendor fix Red Hat Product Security RHSA-2026:10184 · 5 productsFor Red Hat OpenShift AI 2.25.5 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
- Workaround from the vendor Red Hat Product Security RHSA-2026:37275 · 235 productsRed Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2026-03-12
- Last Modified
- 2026-08-24
- NVD status
- Deferred
Frequently asked questions
What is CVE-2026-28356?
Is CVE-2026-28356 actively exploited?
What is the CVSS score for CVE-2026-28356?
Running multipart? Hear about its next vulnerability
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
No credit card required · No monthly cap on website lookups · 250 API requests/month
Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
- Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.
Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.