CVE-2021-29430

Sydent is a reference Matrix identity server. Sydent does not limit the size of requests it receives from HTTP clients. A malicious user could send an HTTP request with a very large body, leading to memory exhaustion and denial of service. Sydent also does not limit response size for requests it makes to remote Matrix homeservers. A malicious homeserver could return a very large response, again leading to memory exhaustion and denial of service. This affects any server which accepts registration requests from untrusted clients. This issue has been patched by releases 89071a1, 0523511, f56eee3. As a workaround request sizes can be limited in an HTTP reverse-proxy. There are no known workarounds for the problem with overlarge responses.

CVSS v3.0 7.5 HIGH
CVSS v2.0 5.0 MEDIUM

7.5^/10

CVSS v3.0 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

5.0^/10

CVSS v2.0 : MEDIUM

Vector : AV:N/AC:L/Au:N/C:N/I:N/A:P

Exploitability : 10.0 / Impact : 2.9

Access Vector NETWORK

Access Complexity LOW

Authentication NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact PARTIAL

References

Link	Resource
https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7	Patch Third Party Advisory
https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d	Patch Third Party Advisory
https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428	Patch Third Party Advisory
https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9	Patch Third Party Advisory
https://pypi.org/project/matrix-sydent/	Product Third Party Advisory
https://github.com/matrix-org/sydent/releases/tag/v2.3.0	Release Notes Third Party Advisory

Advertisement

Configurations

Configuration 1 (hide)

cpe:2.3:a:matrix:sydent:*:*:*:*:*:*:*:*

Information

Published : 2021-04-15 14:15

Updated : 2022-08-03 03:13

NVD link : CVE-2021-29430

Mitre link : CVE-2021-29430

JSON object : View

CWE

CWE-770

Allocation of Resources Without Limits or Throttling

Advertisement

Products Affected

matrix

sydent

{"cve": {"data_type": "CVE", "references": {"reference_data": [{"url": "https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7", "name": "https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7", "tags": ["Patch", "Third Party Advisory"], "refsource": "MISC"}, {"url": "https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d", "name": "https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d", "tags": ["Patch", "Third Party Advisory"], "refsource": "MISC"}, {"url": "https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428", "name": "https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428", "tags": ["Patch", "Third Party Advisory"], "refsource": "MISC"}, {"url": "https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9", "name": "https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9", "tags": ["Patch", "Third Party Advisory"], "refsource": "CONFIRM"}, {"url": "https://pypi.org/project/matrix-sydent/", "name": "https://pypi.org/project/matrix-sydent/", "tags": ["Product", "Third Party Advisory"], "refsource": "MISC"}, {"url": "https://github.com/matrix-org/sydent/releases/tag/v2.3.0", "name": "https://github.com/matrix-org/sydent/releases/tag/v2.3.0", "tags": ["Release Notes", "Third Party Advisory"], "refsource": "MISC"}]}, "data_format": "MITRE", "description": {"description_data": [{"lang": "en", "value": "Sydent is a reference Matrix identity server. Sydent does not limit the size of requests it receives from HTTP clients. A malicious user could send an HTTP request with a very large body, leading to memory exhaustion and denial of service. Sydent also does not limit response size for requests it makes to remote Matrix homeservers. A malicious homeserver could return a very large response, again leading to memory exhaustion and denial of service. This affects any server which accepts registration requests from untrusted clients. This issue has been patched by releases 89071a1, 0523511, f56eee3. As a workaround request sizes can be limited in an HTTP reverse-proxy. There are no known workarounds for the problem with overlarge responses."}]}, "problemtype": {"problemtype_data": [{"description": [{"lang": "en", "value": "CWE-770"}]}]}, "data_version": "4.0", "CVE_data_meta": {"ID": "CVE-2021-29430", "ASSIGNER": "security-advisories@github.com"}}, "impact": {"baseMetricV2": {"cvssV2": {"version": "2.0", "baseScore": 5.0, "accessVector": "NETWORK", "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:P", "authentication": "NONE", "integrityImpact": "NONE", "accessComplexity": "LOW", "availabilityImpact": "PARTIAL", "confidentialityImpact": "NONE"}, "severity": "MEDIUM", "acInsufInfo": false, "impactScore": 2.9, "obtainAllPrivilege": false, "exploitabilityScore": 10.0, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}, "baseMetricV3": {"cvssV3": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}}, "publishedDate": "2021-04-15T21:15Z", "configurations": {"nodes": [{"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:a:matrix:sydent:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionEndExcluding": "2.3.0"}]}], "CVE_data_version": "4.0"}, "lastModifiedDate": "2022-08-03T10:13Z"}