Home/CVE/Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, parse_options_header parsed Content-Dispos
CVE
CVE-2026-53537
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, parse_options_header parsed Content-Dispos
Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, parse_options_header parsed Content-Disposition (and Content-Type) headers with email.message.Message, which transparently applies RFC 2231/5987 decoding. The extended parameter syntax (filename=charset'lang'value, name=..., and the filename0/filename1 continuation form) is decoded and surfaced under the bare filename/name key, and overrides the plain parameter when both are present.
RFC 7578 §4.2 explicitly forbids the filename* form in multipart/form-data. Components that follow RFC 7578, or that do not implement RFC 2231/5987 decoding for multipart/form-data (WAFs, proxies, gateways), may interpret such a header differently. An attacker can exploit that difference to smuggle a different field name or filename past an upstream inspector to the backend.
This vulnerability is fixed in 0.0.30.
LOW · CVSS 3.7
Monitor
- No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
No Sigma yet — build one →
YARA rules0
Look this up elsewhere - one-click external pivots
▸
How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-53537, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked.
EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal.
CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score.
Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits.
PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
EPSS exploitation probability
n/a
No EPSS score in our data for this CVE. EPSS is published daily for scored CVEs - a very new, reserved, or rejected CVE may not have one yet.
CVSS metric silhouette
shape grows toward worst-case
SSVC triage
No SSVC vulnrichment for this CVE. CISA's Vulnrichment program scores newer CVEs (~2024 onwards) plus selected older critical ones. Use the EPSS probability + KEV status to triage instead.
CVSS vector breakdown
Exploitability - how they get in
Attack Vector
Network
Adjacent
Local
Physical
Attack Complexity
Low
High
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Impact - what breaks
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
VECTOR
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N◆
ATT&CK techniques
1Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.
▤ Build a SIEM detection for these techniques▤
CAPEC attack patterns
12Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.
CAPEC-CAPEC-10 · Buffer Overflow via Environment Variables CAPEC-CAPEC-101 · Server Side Include (SSI) Injection CAPEC-CAPEC-104 · Cross Zone Scripting CAPEC-CAPEC-105 · HTTP Request Splitting CAPEC-CAPEC-108 · Command Line Execution through SQL Injection CAPEC-CAPEC-109 · Object Relational Mapping Injection CAPEC-CAPEC-110 · SQL Injection through SOAP Parameter Tampering CAPEC-CAPEC-120 · Double Encoding CAPEC-CAPEC-13 · Subverting Environment Variable Values CAPEC-CAPEC-135 · Format String Injection CAPEC-CAPEC-136 · LDAP Injection CAPEC-CAPEC-14 · Client-side Injection-induced Buffer Overflow
⬡
Weakness Classification
CWE-436Interpretation Conflict
▤
Affected Packages
1Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
PyPI
python-multipart
LOW
fixed in 0.0.30
▤
Related CVEs
8CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row. Not a guess.
CVE-1999-0265
ICMP redirect messages may crash or lock up a host.
same CWE-20
CVE-1999-0726
An attacker can conduct a denial of service in Windows NT by executing a program...
same CWE-20
CVE-1999-0918
Denial of service in various Windows systems via malformed, fragmented IGMP pack...
3
same CWE-20
CVE-1999-0721
Denial of service in Windows NT Local Security Authority (LSA) through a malform...
same CWE-20
CVE-2018-6560
In dbus-proxy/flatpak-proxy.c in Flatpak before 0.8.9, and 0.9.x and 0.10.x befo...
same CWE-436
HIGH
CVE-2018-19966
An issue was discovered in Xen through 4.11.x allowing x86 PV guest OS users to ...
same CWE-436
HIGH
CVE-2019-5892
bgpd in FRRouting FRR (aka Free Range Routing) 2.x and 3.x before 3.0.4, 4.x bef...
same CWE-436
MEDIUM
CVE-2019-0052
The srxpfe process may crash on SRX Series services gateways when the UTM module...
same CWE-436
HIGH
🔗
References & Sources
1Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.