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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-28356

27
FAUCET Score

CVE-2026-28356 is a high-severity Regular Expression Denial of Service (ReDoS) vulnerability affecting the `multipart` Python library, specifically versions prior to 1.2.2, 1.3.1, and 1.4.0-dev. This flaw allows remote attackers to trigger exponential backtracking by sending maliciously crafted HTTP or multipart segment headers, leading to a denial of service for web applications utilizing the library. With a CVSS score of 7.5 (HIGH), the vulnerability is easily exploitable over the network without authentication, primarily impacting system availability. Currently, there is no evidence of active exploitation, public exploit code, or significant community discussion regarding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
DefnullMultipart
< 1.2.2, >= 1.3.0, < 1.3.1CNA affected

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.72%
Probability of exploitation in next 30 days
EPSS Percentile
50.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0072 is in the 26th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

pippatch availablevia ghsa
Product: multipartFixed in: 1.3.1
pippatch availablevia ghsa
Product: multipartFixed in: 1.2.2
ubuntupatch availablevia ubuntu_usn
Product: multipart (questing)Fixed in: 1.2.1-2+deb13u1build0.25.10.1
ubuntupatch availablevia ubuntu_usn
Product: multipart (resolute)Fixed in: 1.3.0-3ubuntu0.1

Vendor Advisories (2)

ubuntuUSN-8343-1

multipart vulnerability

May 28, 2026
pipGHSA-p2m9-wcp5-6qw3high

multipart vulnerable to ReDoS in `parse_options_header()`

Mar 12, 2026

References

access.redhat.com / errata/RHSA-2026:10184
access.redhat.com / errata/RHSA-2026:37275
access.redhat.com / errata/RHSA-2026:42644
access.redhat.com / errata/RHSA-2026:5809
access.redhat.com / errata/RHSA-2026:6761
access.redhat.com / errata/RHSA-2026:6762
access.redhat.com / security/cve/CVE-2026-28356
bugzilla.redhat.com / show_bug.cgi
security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-28356.json
github.com / defnull/multipart/security/advisories/GHSA-p2m9-wcp5-6qw3