Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, when parsing application/x-www-form-urlencoded bodies, QuerystringParser located the field separator with a two step lookup: it first scanned the entire remaining buffer for &, and only when no & existed anywhere ahead did it fall back to scanning for ;. For a body that uses ; as the separator and contains no &, every field iteration performed a full failed & scan over the entire remaining buffer before locating the nearby ;. With N semicolon separated fields in a chunk of size B, this yields O(B^2) byte comparisons per chunk. An attacker can submit a small crafted body of the form a;a;a;... and cause the parser to spend seconds of CPU per request. A handful of concurrent requests can exhaust worker processes. This vulnerability is fixed in 0.0.30.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, when parsing
    application/x-www-form-urlencoded bodies, QuerystringParser located the field separator with a two step
    lookup: it first scanned the entire remaining buffer for &, and only when no & existed anywhere ahead did
    it fall back to scanning for ;. For a body that uses ; as the separator and contains no &, every field
    iteration performed a full failed & scan over the entire remaining buffer before locating the nearby ;.
    With N semicolon separated fields in a chunk of size B, this yields O(B^2) byte comparisons per chunk. An
    attacker can submit a small crafted body of the form a;a;a;... and cause the parser to spend seconds of
    CPU per request. A handful of concurrent requests can exhaust worker processes. This vulnerability is
    fixed in 0.0.30. (CVE-2026-53539)

The version of IBM Cognos Analytics installed on the remote host is 12.1.x prior to 12.1.3 FP2. It is, therefore, affected by multiple vulnerabilities as referenced in the IBM Security Bulletin No. 7287209. These vulnerabilities are applicable only to version 12.1.3 due to newer functionalities and an updated software stack:

  - Arbitrary class instantiation via model manifest in Apache OpenNLP ExtensionLoader. The     ExtensionLoader.instantiateExtension() method loads a class by its fully-qualified name via     Class.forName() and invokes its no-arg constructor, with the class name sourced from the     manifest.properties entry of a model archive. An attacker who can supply a crafted model archive can     cause the static initializer of any class on the classpath to run during model loading.
    (CVE-2026-42027)

  - XML External Entity (XXE) via unsanitized dictionary parsing in Apache OpenNLP     DictionaryEntryPersistor. An attacker who can supply a crafted dictionary file containing a malicious     DOCTYPE declaration can trigger local file disclosure via file:// entity references or server-side     request forgery via http:// entity references during SAX parsing. (CVE-2026-40682)

  - An authenticated attacker may bypass the fix in CVE-2026-34197 by adding a connector using an HTTP     Discovery transport via BrokerView.addNetworkConnector or BrokerView.addConnector through Jolokia if the     activemq-http module is on the classpath, resulting in arbitrary code execution on the Apache ActiveMQ     broker's JVM. (CVE-2026-40466)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES16 / SLES_SAP16 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:22372-1 advisory.

    This update for python-python-multipart fixes the following issues

    - CVE-2026-53537: multipart/form-data with extended parameters can lead to file or parameter smuggling     (bsc#1268506).
    - CVE-2026-53538: urlencoded requests containing semicolons can lead to form field smuggling     (bsc#1268496).
    - CVE-2026-53539: small crafted body can cause a denial of service (bsc#1268500).
    - CVE-2026-53540: crafted request buffers can lead to degrading availability (bsc#1268488).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:21066-1 advisory.

    This update for python-python-multipart fixes the following issues

    - CVE-2026-53537: multipart/form-data with extended parameters can lead to file or parameter smuggling     (bsc#1268506).
    - CVE-2026-53538: urlencoded requests containing semicolons can lead to form field smuggling     (bsc#1268496).
    - CVE-2026-53539: small crafted body can cause a denial of service (bsc#1268500).
    - CVE-2026-53540: crafted request buffers can lead to degrading availability (bsc#1268488).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, when parsing     application/x-www-form-urlencoded bodies, QuerystringParser located the field separator with a two step     lookup: it first scanned the entire remaining buffer for &, and only when no & existed anywhere ahead did     it fall back to scanning for ;. For a body that uses ; as the separator and contains no &, every field     iteration performed a full failed & scan over the entire remaining buffer before locating the nearby ;.
    With N semicolon separated fields in a chunk of size B, this yields O(B^2) byte comparisons per chunk. An     attacker can submit a small crafted body of the form a;a;a;... and cause the parser to spend seconds of     CPU per request. A handful of concurrent requests can exhaust worker processes. This vulnerability is     fixed in 0.0.30. (CVE-2026-53539)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
459324	Echo: python-multipart: security update to 0.0.30	Tenable Cloud Security	Echo Local Security Checks	Local	high
459324	Echo: python-multipart: security update to 0.0.30	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
347959	IBM Cognos Analytics 12.1.x < 12.1.3 FP2 Multiple Vulnerabilities (7287209)	Nessus	CGI abuses	Remote	high
324845	SUSE SLES16 Security Update : python-python-multipart (SUSE-SU-2026:22372-1)	Nessus	SuSE Local Security Checks	Local	medium
324071	openSUSE 16 Security Update : python-python-multipart (openSUSE-SU-2026:21066-1)	Nessus	SuSE Local Security Checks	Local	medium
322153	Linux Distros Unpatched Vulnerability : CVE-2026-53539	Nessus	Misc.	Local	high
443222	SCA: security update for python-multipart (GHSA-5rvq-cxj2-64vf)	Tenable Cloud Security	SCA Checks	Local	high
443222	SCA: security update for python-multipart (GHSA-5rvq-cxj2-64vf)	Tenable Self-Hosted Container Security	SCA Checks	Local	high

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CVE-2026-53539

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