Element-hq vulnerabilities
Published CVEs affecting Element-hq products: 6 record(s), with severity, exploitation and fixes.
CVE-2026-55850
Medium · 5.3
CWE-79 Aug 21, 2026
Element Web: A malicious homeserver can inject HTML in Element Web using its homepage
Element Web is a Matrix web client built using the Matrix React SDK. Prior to 1.12.22, EmbeddedPage in apps/web/src/components/structures/EmbeddedPage.tsx renders homeserver-supplied homepage content through dangerouslySetInnerHTML without passing it through sanitizedHtmlNode. A malicious homeserver can provide crafted HTML that Element Web renders on the homepage; the content security policy prevents JavaScript but not phishing HTML. This issue is fixed in version 1.12.22.
CVE-2026-45078
Medium · 5.5
CWE-770 May 28, 2026
Synapse CPU starvation (Denial of Service)
Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, local authenticated users can cause Synapse to starve other requests of CPU and lead to other requests failing, causing other users to be denied service. This vulnerability is fixed in 1.152.1.
CVE-2026-45076
Low · 2.7
CWE-20 May 28, 2026
Synapse pagination denial of service
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.
CVE-2026-24044
Critical · 9.2
CWE-336 Feb 12, 2026
ESS Community Helm Chart has a weak server key generation method
Element Server Suite Community Edition (ESS Community) deploys a Matrix stack using the provided Helm charts and Kubernetes distribution. The ESS Community Helm Chart secrets initialization hook (using matrix-tools container before 0.5.7) is using an insecure Matrix server key generation method, allowing network attackers to potentially recreate the same key pair, allowing them to impersonate the victim server. The secret is generated by the secrets initialization hook, in the ESS Community Helm Chart values, if both initSecrets.enabled is not set to false and synapse.signingKey is not defined. Given a server key in Matrix authenticates both requests originating from and events constructed on a given server, this potentially impacts confidentiality, integrity and availability of rooms which have a vulnerable server present as a member. The confidentiality of past conversations in end-to-end encrypted rooms is not impacted. The key generation issue was fixed in matrix-tools 0.5.7, released as part of ESS Community Helm Chart 25.12.1.
CVE-2025-62425
High · 8.3
CWE-620 Oct 16, 2025
Matrix Authentication Service account password can be changed using an authenticated session without supplying the current password
MAS (Matrix Authentication Service) is a user management and authentication service for Matrix homeservers, written and maintained by Element. A logic flaw in matrix-authentication-service 0.20.0 through 1.4.0 allows an attacker with access to an authenticated MAS session to perform sensitive operations without entering the current password. These include changing the current password, adding or removing an e-mail address and deactivating the account. The vulnerability only affects instances which have the local password database feature enabled (passwords section in the config). Patched in matrix-authentication-service 1.4.1.
CVE-2025-61672
Medium · 5.3
CWE-1287 Oct 8, 2025
Synapse: Invalid device keys degrade federation functionality
Synapse is an open source Matrix homeserver implementation. Lack of validation for device keys in Synapse before 1.138.3 and in Synapse 1.139.0 allow an attacker registered on the victim homeserver to degrade federation functionality, unpredictably breaking outbound federation to other homeservers. The issue is patched in Synapse 1.138.3, 1.138.4, 1.139.1, and 1.139.2. Note that even though 1.138.3 and 1.139.1 fix the vulnerability, they inadvertently introduced an unrelated regression. For this reason, the maintainers of Synapse recommend skipping these releases and upgrading straight to 1.138.4 and 1.139.2.