Vulnerability in matrix-synapse (CVE-2026-45076)
Summary
Vulnerability in matrix-synapse (CVE-2026-45076). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 1.152.1 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-45076 has been found in matrix-synapse.
Risk of unauthorized operations or information disclosure. CVSS score: 2.7/10.
What to do: upgrade matrix-synapse to 1.152.1 or later.
If unsure, ask your IT team or search "matrix-synapse CVE-2026-45076" on the vendor's site.
CVE-2026-45076 (matrix-synapse) — CWE-20 / CVSS v3 2.7
Attack vector: remote (network-reachable) / no user interaction
Patched: 1.152.1 — apply immediately
Workaround: There are no known workarounds for this issue.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-20) exists in matrix-synapse.
Check the vendor advisory for the affected versions of matrix-synapse.
Severity: Low (CVSS 2.7/10). Risk of unauthorized operations or information disclosure.
Update to 1.152.1.
Workaround: There are no known workarounds for this issue.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'matrix-synapse' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'matrix-synapse' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
matrix-synapseを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
There are no known workarounds for this issue.パッチが適用されるまでの応急処置として、There are no known workarounds for this issue. を実施。回避策の副作用 (機能低下) を確認した上で。
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3Apply patch patch
Upgrade matrix-synapse to 1.152.1ステージング環境で 1.152.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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4Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-45076 matrix-synapse Fixed in: 1.152.1-1
- Ubuntu UBUNTU-CVE-2026-45076 matrix-synapse
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- web github.com
- web github.com