CVE-2026-55440 (GCVE-0-2026-55440)
Vulnerability from cvelistv5 – Published: 2026-07-16 15:35 – Updated: 2026-07-16 16:23
VLAI
EPSS
VEX
Title
Microsoft UFO: COMMAND_RESULTS handler creates unowned sessions, allowing authenticated session-squatting denial of service
Summary
Microsoft UFO open-source framework for intelligent automation across devices and platforms. Prior to 3.0.7, the COMMAND_RESULTS handler in ufo/server/ws/handler.py called get_or_create_session in ufo/server/services/session_manager.py without owner_client_id, allowing an authenticated client to create an unowned attacker-chosen session_id such as constellation_task_id = f"{task_name}@{task_id}" and deny the legitimate owner or exhaust memory with phantom sessions. This issue is fixed in version 3.0.7.
Severity
6.5 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-16 16:23 UTC
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/microsoft/UFO/security/advisor… | x_refsource_CONFIRM |
| https://github.com/microsoft/UFO/commit/cc653bde7… | x_refsource_MISC |
| https://github.com/microsoft/UFO/releases/tag/3.0.7 | x_refsource_MISC |
Impacted products
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-55440",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-16T16:23:07.186935Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-16T16:23:56.463Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "UFO",
"vendor": "microsoft",
"versions": [
{
"status": "affected",
"version": "\u003c 3.0.7"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Microsoft UFO open-source framework for intelligent automation across devices and platforms. Prior to 3.0.7, the COMMAND_RESULTS handler in ufo/server/ws/handler.py called get_or_create_session in ufo/server/services/session_manager.py without owner_client_id, allowing an authenticated client to create an unowned attacker-chosen session_id such as constellation_task_id = f\"{task_name}@{task_id}\" and deny the legitimate owner or exhaust memory with phantom sessions. This issue is fixed in version 3.0.7."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-400",
"description": "CWE-400: Uncontrolled Resource Consumption",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-862",
"description": "CWE-862: Missing Authorization",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-16T15:35:51.346Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf"
},
{
"name": "https://github.com/microsoft/UFO/commit/cc653bde75337ab60c320e6b7cb61b86ba6ca948",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/microsoft/UFO/commit/cc653bde75337ab60c320e6b7cb61b86ba6ca948"
},
{
"name": "https://github.com/microsoft/UFO/releases/tag/3.0.7",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/microsoft/UFO/releases/tag/3.0.7"
}
],
"source": {
"advisory": "GHSA-hxjv-fmjf-wmjf",
"discovery": "UNKNOWN"
},
"title": "Microsoft UFO: COMMAND_RESULTS handler creates unowned sessions, allowing authenticated session-squatting denial of service"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-55440",
"datePublished": "2026-07-16T15:35:51.346Z",
"dateReserved": "2026-06-16T21:59:57.017Z",
"dateUpdated": "2026-07-16T16:23:56.463Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-55440",
"date": "2026-09-20",
"epss": "0.0126",
"percentile": "0.68305"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"product": "UFO",
"vendor": "microsoft",
"versions": [
{
"status": "affected",
"version": "\u003c 3.0.7"
}
]
}
],
"source": "security-advisories@github.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Microsoft UFO open-source framework for intelligent automation across devices and platforms. Prior to 3.0.7, the COMMAND_RESULTS handler in ufo/server/ws/handler.py called get_or_create_session in ufo/server/services/session_manager.py without owner_client_id, allowing an authenticated client to create an unowned attacker-chosen session_id such as constellation_task_id = f\"{task_name}@{task_id}\" and deny the legitimate owner or exhaust memory with phantom sessions. This issue is fixed in version 3.0.7."
}
],
"id": "CVE-2026-55440",
"lastModified": "2026-07-16T17:46:04.350",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 3.6,
"source": "security-advisories@github.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-55440",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-16T16:23:07.186935Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-07-16T16:19:13.787",
"references": [
{
"source": "security-advisories@github.com",
"url": "https://github.com/microsoft/UFO/commit/cc653bde75337ab60c320e6b7cb61b86ba6ca948"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/microsoft/UFO/releases/tag/3.0.7"
},
{
"source": "security-advisories@github.com",
"url": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"url": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf"
}
],
"sourceIdentifier": "security-advisories@github.com",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-400"
},
{
"lang": "en",
"value": "CWE-862"
}
],
"source": "security-advisories@github.com",
"type": "Secondary"
}
]
}
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-55440",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-16T16:23:07.186935Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-07-16T16:23:27.896Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"exploit"
],
"url": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "UFO",
"vendor": "microsoft",
"versions": [
{
"status": "affected",
"version": "\u003c 3.0.7"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Microsoft UFO open-source framework for intelligent automation across devices and platforms. Prior to 3.0.7, the COMMAND_RESULTS handler in ufo/server/ws/handler.py called get_or_create_session in ufo/server/services/session_manager.py without owner_client_id, allowing an authenticated client to create an unowned attacker-chosen session_id such as constellation_task_id = f\"{task_name}@{task_id}\" and deny the legitimate owner or exhaust memory with phantom sessions. This issue is fixed in version 3.0.7."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 6.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-400",
"description": "CWE-400: Uncontrolled Resource Consumption",
"lang": "en",
"type": "CWE"
}
]
},
{
"descriptions": [
{
"cweId": "CWE-862",
"description": "CWE-862: Missing Authorization",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-16T15:35:51.346Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/microsoft/UFO/security/advisories/GHSA-hxjv-fmjf-wmjf"
},
{
"name": "https://github.com/microsoft/UFO/commit/cc653bde75337ab60c320e6b7cb61b86ba6ca948",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/microsoft/UFO/commit/cc653bde75337ab60c320e6b7cb61b86ba6ca948"
},
{
"name": "https://github.com/microsoft/UFO/releases/tag/3.0.7",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/microsoft/UFO/releases/tag/3.0.7"
}
],
"source": {
"advisory": "GHSA-hxjv-fmjf-wmjf",
"discovery": "UNKNOWN"
},
"title": "Microsoft UFO: COMMAND_RESULTS handler creates unowned sessions, allowing authenticated session-squatting denial of service"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-55440",
"datePublished": "2026-07-16T15:35:51.346Z",
"dateReserved": "2026-06-16T21:59:57.017Z",
"dateUpdated": "2026-07-16T16:23:56.463Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…