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Exploitation reportedNot in CISA KEV yetFix available

CVE-2018-10657

Exploitation reported by one source. First attested on 2018-05-02 by GCVE · kevintel.

  • Published2018-05-02
  • Fixed in0.28.1
  • WeaknessCWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2018-05-0216:00Listed as exploited by GCVEGCVE
  2. 2018-05-0216:00Exploitation first reportedGCVE
  3. 2018-05-0216:29CVE publishedNVD

Versions per branch

NVD · OSV
Matrix synapse
BranchAffectedFixed in
0.28< 0.28.10.28.1

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • matrix-synapseUbuntu:Pro:18.04:LTSall versions · fixed in 0.24.0+dfsg-1ubuntu0.1~esm1

Vendor advisories

  • CVE-2018-10657 Red Hat Product Security

    matrix-synapse: Injection of malicious events with a depth size of 2^63-1 can cause a denial of service to making rooms unusable

Full record on NVD

Fix

  1. Update Matrix synapse to 0.28.1

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • GCVEexploitation2018-05-02
  • NVDCVSS 3.07.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • NVDweakness (CWE)CWE-20read 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2023-07-25

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2018-05-02
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-vmcc-4p4x-x7wg

Frequently asked questions

What is CVE-2018-10657?

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.

Is CVE-2018-10657 actively exploited?

Active exploitation of CVE-2018-10657 has not been confirmed. Its EPSS score was 1.5% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-10657?

CVE-2018-10657 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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