Medium
Synapse pagination denial of service
Type: advisorySources: OSV
Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This vulnerability is fixed in 1.152.1.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-45076
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 02:05 UTC · Revision 1
Source evidence
Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This vulnerability is fixed in 1.152.1.
osv:CVE-2026-45076
Complete source record
{
"id": "2b1f230f1fc58752901edafd477c63c0a5ecda5684109f2a764314bf96d1b4d0",
"url": "https://osv.dev/vulnerability/CVE-2026-45076",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Synapse pagination denial of service",
"summary": "Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This vulnerability is fixed in 1.152.1.",
"evidence": "osv:CVE-2026-45076",
"products": [],
"severity": "medium",
"structured": {
"id": "CVE-2026-45076",
"aliases": [
"CVE-2026-45076",
"GHSA-6qf2-7x63-mm6v",
"PYSEC-2026-194"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/element-hq/synapse",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "d97b5b9e21681792d78c5d58243fc483c664b66e"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "1.152.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"cpe": "cpe:2.3:a:element:synapse:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "1.152.1"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
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"v1.152.0rc1",
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45076.json"
}
}
],
"modified": "2026-10-28T02:30:32.441463360Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45076.json",
"https://github.com/element-hq/synapse/security/advisories/GHSA-6qf2-7x63-mm6v",
"https://nvd.nist.gov/vuln/detail/CVE-2026-45076"
],
"provider_metadata": {
"cwe_ids": [
"CWE-20"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45076.json"
}
},
"related_cves": [
{
"value": "CVE-2026-45076",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 499542,
"published_at": "2026-05-28T15:50:25.842+00:00"
}