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4 vulnerabilities found for misp-stix by misp
CVE-2026-77761 (GCVE-0-2026-77761)
Vulnerability from cvelistv5
Published
2026-08-21 10:11
Modified
2026-08-21 12:00
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-459 - Incomplete Cleanup
Summary
A parser state isolation vulnerability in misp-stix could cause data from a previously processed STIX document to be retained and incorporated into the MISP event generated from a subsequent document when the same parser instance is reused.
Several STIX 1 and STIX 2 parser components maintained per-document state that was not completely cleared between conversions. In the STIX 2 parser, galaxy and galaxy-cluster information, including custom galaxy clusters, could survive a parser reset and subsequently be associated with objects from another bundle.
The STIX 1 parsers were affected by the same underlying state-management issue. Depending on the parser type, retained information could include galaxies, references, passive DNS bookkeeping, package titles, dates, and timestamps. As a result, parsing a second STIX package with an already-used parser could produce a MISP event containing information that was present only in the previously processed package. For example, a generated event could inherit passive DNS records from an earlier document, reference unrelated galaxy information, combine titles from different packages, or use timestamps originating from another conversion.
The issue primarily affects applications using the misp-stix API directly and reusing parser instances across independent STIX documents. Normal conversion entry points that instantiate a new parser for each file are not affected by this particular reuse scenario.
An attacker able to influence documents processed by such a long-lived parser could potentially cause information from one conversion to contaminate a subsequent MISP event. This can affect the integrity of generated threat intelligence, resulting in incorrect associations, misleading contextual information, or unrelated indicators being attributed to an event. In environments where consecutive documents have different access controls or distribution scopes, the retained state could additionally result in limited disclosure of information from a previously processed document.
Successful exploitation depends on the consuming application reusing the same parser instance and on the ordering of processed documents, which increases attack complexity. No direct availability impact or code execution is involved.
References
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CVE-2026-77755 (GCVE-0-2026-77755)
Vulnerability from cvelistv5
Published
2026-08-21 09:55
Modified
2026-08-21 12:09
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-400 - Uncontrolled Resource Consumption
Summary
A denial-of-service vulnerability was identified in misp-stix when processing attacker-controlled STIX 1 or STIX 2 documents.
The STIX import code used sys.exit() to handle several parsing and loading failures. Because SystemExit inherits from BaseException rather than Exception, these failures bypassed the exception handlers used by callers of the library. As a result, a malformed STIX document could terminate a long-running importer process instead of returning a recoverable parsing error.
Additionally, no limit was imposed on the size of STIX documents before parsing. A submitted document was therefore read and materialised in memory before its validity or type was evaluated. Depending on the document and parsing path, processing could consume approximately two to seven times the input size in memory, allowing a sufficiently large STIX document to cause excessive memory and CPU consumption and potentially terminate or severely degrade the importing service.
An attacker able to provide STIX content to a MISP-STIX import workflow could exploit either condition to affect availability. A malformed document could cause abnormal process termination through an uncaught SystemExit, while a large document could exhaust resources during deserialisation and conversion.
The fixes replace process-terminating sys.exit() calls with catchable exceptions such as STIXLoadingError and MissingSTIXContentError, and extend exception handling around the complete STIX detection and conversion process. The importer also now enforces an input-size limit before parsing. The default maximum is 100 MB, can be adjusted by callers, and can explicitly be disabled when required. STIX 1 inputs are additionally checked for the expected root element before the complete XML tree is constructed.
ImpactSuccessful exploitation can cause:
* termination of a long-running MISP-STIX importer;
* excessive memory allocation;
* excessive CPU consumption;
* degradation or temporary unavailability of services relying on the converter;
* interruption of batch or automated STIX ingestion workflows.
References
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CVE-2026-77751 (GCVE-0-2026-77751)
Vulnerability from cvelistv5
Published
2026-08-21 09:48
Modified
2026-08-25 19:08
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Summary
A path traversal vulnerability existed in the handling of MISP object template names during STIX 2 import and MISP-to-STIX 2 export.
MISP object names are passed to PyMISP's object-template resolution mechanism, which constructs a filesystem path by joining the configured MISP object-template directory, the object name, and definition.json. An object name originating from untrusted STIX or MISP content was not sufficiently restricted before being used in this filesystem path.
An attacker able to supply a crafted object name containing path separators or traversal sequences such as ../ could therefore cause template resolution to escape the expected template directory and attempt to load a definition.json file from another location accessible to the process.
During STIX 2 import, an attacker-controlled x_misp_name from a custom STIX object could directly reach this template-resolution mechanism.
The issue could also become persistent. A malicious object name stored in a MISP event could later be processed again during STIX 2 export. Consequently, content originally introduced in one security context could trigger filesystem access later when the event is exported by a process operating with different or greater privileges.
If a suitable definition.json file exists outside the intended template directory, its contents may be interpreted as a MISP object template and fields from that file copied into the converted object. This can result in unintended disclosure of locally accessible data represented by the template file and modification of the resulting object's metadata or semantics.
The patches introduce strict validation of object-template names. Valid names are restricted to a single path component containing letters, digits, hyphens, or underscores. Names that do not meet these requirements are replaced with the generic unknown-template name before reaching PyMISP template resolution. The original rejected name is preserved in the object's comment and a warning is generated, preventing traversal while retaining the source information.
References
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CVE-2026-77710 (GCVE-0-2026-77710)
Vulnerability from cvelistv5
Published
2026-08-21 08:54
Modified
2026-08-21 17:19
Severity ?
VLAI Severity ?
EPSS score ?
CWE
- CWE-20 - Improper Input Validation
Summary
A vulnerability in misp-stix could allow a crafted STIX document to influence security-sensitive MISP attribute metadata during import.
The STIX import logic automatically selected between the internal MISP parser and the external STIX parser based on metadata contained in the STIX document itself. For STIX2, the presence of MISP-specific tool labels could cause a document to be classified as originating from MISP; similarly, STIX1 relied on the document title. These classification indicators are fully controlled by the STIX producer and therefore cannot constitute a trusted indication of the document's origin. The accompanying fix explicitly notes that the parser choice was previously based solely on labels or header titles that any producer could write, and introduces an explicit classification parameter allowing callers to override this detection.
When STIX2 content was handled as an internal MISP export, attributes contained in an x-misp-object were converted by copying the complete x_misp_attributes dictionary and passing it directly to misp_object.add_attribute(). Consequently, a crafted STIX bundle could supply fields that were not part of the expected STIX-to-MISP round-trip format, including security-sensitive properties such as distribution, sharing_group_id, tags, or other MISP attribute fields.
An attacker able to provide a STIX document for import could therefore spoof the markers used to identify MISP-generated content and inject additional attribute properties. This could alter the distribution, sharing restrictions, classification, or semantic metadata of imported attributes, potentially causing information to be shared contrary to the importing organization's policy or influencing downstream processing and automation based on attacker-controlled tags or metadata.
The vulnerability results from dynamically assigning externally supplied object properties without restricting them to an expected set of attributes, matching CWE-915. MITRE specifically describes this weakness as accepting externally influenced fields without controlling which object attributes may be modified and recommends an allow-list, which is the approach implemented by the patch. The parser-selection issue additionally corresponds to CWE-807, because an untrusted value was used to make a security-relevant trust/classification decision.
The attack is also consistent with CAPEC-153 (Input Data Manipulation), in which an attacker controls the structure or flags of supplied data so that the target selects a different processing path or interprets the content differently than intended.
References
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