Matrix Synapse before 0.28.1 is prone to a denial of service flaw where malicious events injected with depth = 2^63 - 1 render rooms unusable, related to federation/federation_base.py and handlers/message.py, as exploited in the wild in April 2018.
CVE-2018-10657
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 36% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 71.4%
- KEV
- Not listed
Published
May 2, 2018
Last Modified
November 21, 2024
References (4)
- cve@mitrehttps://github.com/matrix-org/synapse/commit/33f469ba19586bbafa0cf2c7d7c35463bdab87eb
- cve@mitrehttps://matrix.org/blog/2018/05/01/security-update-synapse-0-28-1/
- af854a3a-2127-422b-91ae-364da2661108https://github.com/matrix-org/synapse/commit/33f469ba19586bbafa0cf2c7d7c35463bdab87eb
- af854a3a-2127-422b-91ae-364da2661108https://matrix.org/blog/2018/05/01/security-update-synapse-0-28-1/
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | matrix-synapse (0.24.0+dfsg-1ubuntu0.1~esm1) @ bionic | 2026-05-28 | ubuntu |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| matrix-synapse | — | 0.28.1 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 8× in last 7d / 42× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-11 08:24 UTCEPSS rescore
- 2026-07-09 19:06 UTCEPSS rescore
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- 2026-07-05 02:27 UTCEPSS rescore
- 2026-07-04 08:56 UTCOSV refresh
- 2026-07-04 06:28 UTCEPSS rescore
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- 2026-07-02 16:54 UTCEPSS rescore
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- 2026-06-30 23:19 UTCEPSS rescore
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- 2026-06-28 14:04 UTCEPSS rescore
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- 2026-06-23 21:30 UTCEPSS rescore
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- 2026-06-21 14:54 UTCEPSS rescore
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- 2026-06-18 17:50 UTCEPSS rescore
- 2026-06-17 17:50 UTCEPSS rescore
- 2026-06-16 17:50 UTCEPSS rescore
- 2026-06-15 20:39 UTCOSV refresh
- 2026-06-15 17:45 UTCEPSS rescore
- 2026-06-14 23:14 UTCEPSS rescore
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- 2026-06-06 13:45 UTCEPSS rescore
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- 2026-05-31 22:28 UTCEPSS rescore
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- 2026-05-29 13:41 UTCEPSS rescore
- 2026-05-28 13:42 UTCEPSS rescore
- 2026-05-28 13:42 UTCEPSS rescore
- 2026-05-28 08:28 UTCEG score recompute
- 2026-05-28 08:28 UTCVendor advisory
- 2026-05-27 13:38 UTCEPSS rescore
- 2026-05-27 13:38 UTCEPSS rescore
- 2026-05-26 13:42 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-26 07:17 UTCEPSS rescore
- 2026-05-23 10:01 UTCOSV refresh
Frequently asked(5)
What is CVE-2018-10657?
When was CVE-2018-10657 disclosed?
Is CVE-2018-10657 actively exploited?
What is the CVSS score of CVE-2018-10657?
How do I remediate CVE-2018-10657?
Dependency Blast Radius
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