CVE-2026-45076

Synapse pagination denial of service

LOW
2.7
CVSS Score
Published: May 28, 2026 at 03:50 PM UTC
Updated: October 26, 2026 at 01:10 PM UTC
2 products affected across 2 vendorsSynapseSynapse

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Severity
LOW2.7
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.152.1
Affected range stops below 1.152.1, so it looks safe — our inference, not a vendor statement
v < 1.152.1
Affected range stops below 1.152.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-20

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