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Matrix Synapse vulnerabilities
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element-hq synapse
Synapse vulnerable to federation denial of service via malformed events
CVE-2025-30355
Fix available
7.1 High
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element-hq synapse
Synapse unauthenticated writes to the media repository allow planting of problematic content
CVE-2024-37303
Fix available
5.3 Medium
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element-hq synapse
Synapse denial of service through media disk space consumption
CVE-2024-37302
Fix available
7.5 High
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element-hq synapse
Synapse allows unsupported content types to lead to memory exhaustion
CVE-2024-52805
Fix available
8.2 High
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element-hq synapse
Synapse allows a a malformed invite to break the invitee's `/sync`
CVE-2024-52815
Fix available
8.7 High
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element-hq synapse
Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders
CVE-2024-53863
Fix available
8.2 High
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element-hq synapse, fedoraproject fedora +1 more
Synapse's V2 state resolution weakness allows DoS from remote room members
CVE-2024-31208
Fix available
6.5 Medium
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element-hq synapse, fedoraproject fedora +1 more
Synapse vulnerable to leak of remote user device information
CVE-2023-43796
Fix available
5.3 Medium
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element-hq synapse, fedoraproject fedora +1 more
matrix-synapse vulnerable to denial of service due to malicious server ACL events
CVE-2023-45129
Fix available
4.9 Medium
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element-hq synapse, fedoraproject fedora +1 more
Improper validation of receipts allows forged read receipts in matrix synapse
CVE-2023-42453
Fix available
3.1 Low
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element-hq synapse, fedoraproject fedora +1 more
Temporary storage of plaintext passwords during password changes in matrix synapse
CVE-2023-41335
Fix available
3.7 Low
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element-hq synapse
URL deny list bypass via oEmbed and image URLs when generating previews in Synapse
CVE-2023-32683
Fix available
3.5 Low
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element-hq synapse
Improper checks for deactivated users during login in synapse
CVE-2023-32682
Fix available
5.4 Medium
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element-hq synapse
Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites
CVE-2023-32323
Fix available
5.0 Medium
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element-hq synapse
Synapse Denial of service due to incorrect application of event authorization rules during state resolution
CVE-2022-39374
Fix available
6.5 Medium
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element-hq synapse
Synapse does not apply enough checks to servers requesting auth events of events in a room
CVE-2022-39335
Fix available
5.0 Medium
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element-hq synapse
Synapse vulnerable to denial of service (DoS) due to incorrect application of event authorization rules
CVE-2022-31152
Fix available
6.4 Medium
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element-hq synapse, fedoraproject fedora +1 more
URL previews can crash Synapse media repositories or Synapse monoliths
CVE-2022-31052
Fix available
6.5 Medium
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element-hq synapse
Uncontrolled Resource Consumption in Matrix Synapse
CVE-2022-41952
Fix available
6.5 Medium
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element-hq synapse, fedoraproject fedora +1 more
Path traversal in Matrix Synapse
CVE-2021-41281
Fix available
7.5 High
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element-hq synapse, fedoraproject fedora +1 more
Improper authorisation of /members discloses room membership to non-members
CVE-2021-39164
Fix available
3.1 Low
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element-hq synapse, fedoraproject fedora +1 more
Adding a private/unlisted room to a community exposes room metadata in an unauthorised manner.
CVE-2021-39163
Fix available
3.1 Low
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element-hq synapse, fedoraproject fedora +1 more
Denial of service in Matrix Synapse
CVE-2021-29471
Fix available
3.7 Low
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element-hq synapse, fedoraproject fedora +1 more
Open redirect via transitional IPv6 addresses on dual-stack networks
CVE-2021-21392
Fix available
6.3 Medium
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element-hq synapse, fedoraproject fedora +1 more
Denial of service (via resource exhaustion) due to improper input validation on groups/communities endpoints
CVE-2021-21393
Fix available
5.3 Medium
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element-hq synapse, fedoraproject fedora +1 more
Denial of service (via resource exhaustion) due to improper input validation on third-party identifier endpoints
CVE-2021-21394
Fix available
5.3 Medium
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element-hq synapse, fedoraproject fedora +1 more
HTML injection in email and account expiry notifications
CVE-2021-21333
Fix available
6.1 Medium
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element-hq synapse, fedoraproject fedora +1 more
Cross-site scripting (XSS) vulnerability in the password reset endpoint
CVE-2021-21332
Fix available
6.9 Medium
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element-hq synapse, fedoraproject fedora +1 more
Open redirects on some federation and push requests
CVE-2021-21273
Fix available
3.1 Low
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element-hq synapse, fedoraproject fedora +1 more
Denial of service attack via .well-known lookups
CVE-2021-21274
Fix available
4.3 Medium
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element-hq synapse, fedoraproject fedora +1 more
Denial of service attack via incorrect parameters to federation APIs
CVE-2020-26257
Fix available
6.5 Medium
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matrix synapse, fedoraproject fedora +1 more
Denial of service attack due to invalid JSON
CVE-2020-26890
Fix available
7.5 High
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matrix synapse
Cross-site scripting (XSS) vulnerability in the fallback authentication endpoint
CVE-2020-26891
Fix available
6.1 Medium
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matrix synapse
Improper Verification of Cryptographic Signature in matrix-synapse
CVE-2019-18835
Fix available
9.8 Critical
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matrix sydent, synapse +1 more
matrix-sydent and matrix-synapse Use Cryptographically Weak PRNG
CVE-2019-11842
Fix available
7.5 High
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matrix synapse, fedoraproject fedora +1 more
Matrix Synapse Predictable Secret Key
CVE-2019-5885
Fix available
7.5 High
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matrix synapse, debian linux +1 more
Matrix Synapse Improper Signature Validation
CVE-2018-16515
Fix available
8.8 High
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matrix synapse
Matrix Synapse Authorization Error
CVE-2018-12423
Fix available
7.5 High
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matrix synapse
Matrix Synapse Security Filtering Flaw
CVE-2018-12291
Fix available
7.5 High
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matrix synapse
Matrix Synapse DoS
CVE-2018-10657
Fix available
7.5 High