Vulnerability Name:

CVE-2020-26890 (CCN-192313)

Assigned:2020-11-23
Published:2020-11-23
Updated:2021-07-21
Summary: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 attack against the federation and common Matrix clients. If such a malformed event is accepted into the room's state, the impact is long-lasting and is not fixed by an upgrade to a newer version, requiring the event to be manually redacted instead. Since events are replicated to servers of other room members, the impact is not constrained to the server of the event sender.
CVSS v3 Severity:7.5 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
7.5 High (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:5.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
7.8 High (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
Vulnerability Type:CWE-74
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2020-26890

Source: XF
Type: UNKNOWN
matrix-cve202026890-dos(192313)

Source: CCN
Type: Synapse GIT Repository
Denial of service attack due to invalid JSON

Source: MISC
Type: Patch, Third Party Advisory
https://github.com/matrix-org/synapse/security/advisories/GHSA-4mp3-385r-v63f

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2020-2578d943d2

Source: FEDORA
Type: Mailing List, Third Party Advisory
FEDORA-2020-b90dac7fc4

Source: CCN
Type: WhiteSource Vulnerability Database
CVE-2020-26890

Vulnerable Configuration:Configuration 1:
  • cpe:/a:matrix:synapse:*:*:*:*:*:*:*:* (Version < 1.20.0)

    • Configuration 2:
  • cpe:/o:fedoraproject:fedora:32:*:*:*:*:*:*:*
  • OR cpe:/o:fedoraproject:fedora:33:*:*:*:*:*:*:*

    • Configuration CCN 1:
  • cpe:/a:matrix:synapse:1.19.0:-:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    matrix synapse *
    fedoraproject fedora 32
    fedoraproject fedora 33
    matrix synapse 1.19.0 -