vulnwire
6.5med

CVE-2020-26257

Denial of service attack via incorrect parameters to federation APIs

Also known as GHSA-hxmp-pqch-c8mm, PYSEC-2020-236

Published 5 y ago · modified 58 d ago · JSON

CVSS
6.5
v3.1 · CNA
CISA KEV
No
not known exploited
EPSS
2.4%
percentile 84%
Public exploits
0
none known

Matrix is an ecosystem for open federated Instant Messaging and VoIP. Synapse is a reference "homeserver" implementation of Matrix. A malicious or poorly-implemented homeserver can inject malformed events into a room by specifying a different room id in the path of a `/send_join`, `/send_leave`, `/invite` or `/exchange_third_party_invite` request. This can lead to a denial of service in which future events will not be correctly sent to other servers over federation. This affects any server which accepts federation requests from untrusted servers. The Matrix Synapse reference implementation before version 1.23.1 the implementation is vulnerable to this injection attack. Issue is fixed in version 1.23.1. As a workaround homeserver administrators could limit access to the federation API to trusted servers (for example via `federation_domain_whitelist`).

Exploit prediction (EPSS)

2.39% probability of exploitation in the next 30 days, higher than 84% of all scored CVEs.

CVSS scores

Assigned byVersionScoreVector
CNA3.16.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA3.16.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD3.16.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD2.04.0AV:N/AC:L/Au:S/C:N/I:N/A:P
GitHub3.16.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected packages

EcosystemPackageAffectedFixed in
pypimatrix-synapse
<1.23.1
1.23.1

Affected products

  • matrix-org synapse

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

References

  • github.com /matrix-org/synapse/security/advisories/GHSA-hxmp-pqch-c8mm · x_refsource_CONFIRM, x_transferred
  • github.com /matrix-org/synapse/pull/8776 · x_refsource_MISC, x_transferred
  • github.com /matrix-org/synapse/commit/3ce2f303f15f6ac3dc352298972dc6e04d9b7a8b · x_refsource_MISC, x_transferred
  • github.com /matrix-org/synapse/blob/develop/CHANGES.md#synapse-1231-2020-12-09 · x_refsource_MISC, x_transferred
  • lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/QR4MMYZKX5N5GYGH4H5LBUUC · vendor-advisory, x_refsource_FEDORA, x_transferred
  • lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/DBTIU3ZNBFWZ56V4X7JIAD33 · vendor-advisory, x_refsource_FEDORA, x_transferred
  • nvd.nist.gov /vuln/detail/CVE-2020-26257 · advisory
  • github.com /pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2020-236.yaml · web
  • lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/DBTIU3ZNBFWZ56V4X7JIAD33V5 · web
  • lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/QR4MMYZKX5N5GYGH4H5LBUUC5T · web
  • lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/QR4MMYZKX5N5GYGH4H5LBUUC5T · web
  • lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/DBTIU3ZNBFWZ56V4X7JIAD33V5 · web

Sources

vulnwire keeps one entry per vulnerability: the CVE id wins, then GHSA; records that alias each other are merged. Machine-readable: JSON.