CVE-2020-26890
Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of m.room.member events, allowing remote attackers to execute a denial of service
02 Description
Matrix Synapse before 1.20.0 erroneously permits non-standard NaN, Infinity, and -Infinity JSON values in fields of m.room.member events, allowing remote attackers to execute a denial of service
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 3.00% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 87.3% of scored records. A rank, not a probability.
- NVD base score
- 7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2020-11-24 02:07Z5 YR AGO
- Last updated
- 2024-08-04 16:03Z2 YR AGO
- Reserved
- 2020-10-08
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- CWE-20Improper Input ValidationClass
- Data version
- 5.1
- Document digest
- 815cdeaffaac5c28b90cfb2aa47dadd1fd13265c5d7f2e5d5ddc15e302c77588
05 Affected products
06 References
- github.comhttps://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f
- lists.fedoraproject.orgFEDORA-2020-b90dac7fc4https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U34DPP4ZLOEDUY2ZCWOHQPU5GA5LYNUQ/
- lists.fedoraproject.orgFEDORA-2020-2578d943d2https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G7YXMMYQP46PYL664JQUXCA3LPBJU7DQ/
07 Fixed in
Arch Linux
- matrix-synapse Fixed in 1.20.1-1
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
Ubuntu Pro 18.04 LTS
- matrix-synapse No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 20.04 LTS
- matrix-synapse No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.