GHSA-WMG4-8CP2-HPG9
Vulnerability from github – Published: 2021-04-19 14:54 – Updated: 2024-09-24 15:43
VLAI
Summary
Sydent vulnerable to denial of service attack via memory exhaustion
Details
Impact
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 disk space 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.
Patches
Patched by 89071a1, 0523511, f56eee3.
Workarounds
Request sizes can be limited in an HTTP reverse-proxy.
There are no known workarounds for the problem with overlarge responses.
For more information
If you have any questions or comments about this advisory, email us at security@matrix.org.
Severity
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "matrix-sydent"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.3.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2021-29430"
],
"database_specific": {
"cwe_ids": [
"CWE-20",
"CWE-400",
"CWE-770"
],
"github_reviewed": true,
"github_reviewed_at": "2021-04-15T20:49:34Z",
"nvd_published_at": "2021-04-15T21:15:00Z",
"severity": "HIGH"
},
"details": "### Impact\n\nSydent 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 disk space exhaustion and denial of service.\n\nSydent 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.\n\nThis affects any server which accepts registration requests from untrusted clients.\n\n### Patches\n\nPatched by 89071a1, 0523511, f56eee3.\n\n### Workarounds\n\nRequest sizes can be limited in an HTTP reverse-proxy.\n\nThere are no known workarounds for the problem with overlarge responses.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at security@matrix.org.",
"id": "GHSA-wmg4-8cp2-hpg9",
"modified": "2024-09-24T15:43:44Z",
"published": "2021-04-19T14:54:04Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/matrix-org/sydent/security/advisories/GHSA-wmg4-8cp2-hpg9"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-29430"
},
{
"type": "WEB",
"url": "https://github.com/matrix-org/sydent/commit/0523511d2fb40f2738f8a8549868f44b96e5dab7"
},
{
"type": "WEB",
"url": "https://github.com/matrix-org/sydent/commit/89071a1a754c69a50deac89e6bb74002d4cda19d"
},
{
"type": "WEB",
"url": "https://github.com/matrix-org/sydent/commit/f56eee315b6c44fdd9f6aa785cc2ec744a594428"
},
{
"type": "PACKAGE",
"url": "https://github.com/matrix-org/sydent"
},
{
"type": "WEB",
"url": "https://github.com/matrix-org/sydent/releases/tag/v2.3.0"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/matrix-sydent/PYSEC-2021-21.yaml"
},
{
"type": "WEB",
"url": "https://pypi.org/project/matrix-sydent"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Sydent vulnerable to denial of service attack via memory exhaustion"
}
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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.
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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.
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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.
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