CVE-2020-26257

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

2.39% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 83.8% of scored records. A rank, not a probability.

NVD base score

6.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/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.

Published

2020-12-09 18:25Z5 YR AGO

Last updated

2024-08-04 15:56Z2 YR AGO

Reserved

2020-10-01

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

Medium (CVSS 6.5)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weaknesses

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base
• CWE-400Uncontrolled Resource ConsumptionClass

Data version

5.1

Document digest

41d940d3a152bf2f3f7aa06d82908fceaf66442f6e1a959aeee947b49dc848c2

• github.comhttps://github.com/matrix-org/synapse/security/advisories/GHSA-hxmp-pqch-c8mmx_refsource_CONFIRM
• github.comhttps://github.com/matrix-org/synapse/pull/8776x_refsource_MISC
• github.comhttps://github.com/matrix-org/synapse/commit/3ce2f303f15f6ac3dc352298972dc6e04d9b7a8bx_refsource_MISC
• github.comhttps://github.com/matrix-org/synapse/blob/develop/CHANGES.md#synapse-1231-2020-12-09x_refsource_MISC
• lists.fedoraproject.orgFEDORA-2020-a2172c484dhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QR4MMYZKX5N5GYGH4H5LBUUC5TLAFHI7/vendor-advisoryx_refsource_FEDORA
• lists.fedoraproject.orgFEDORA-2020-eeb66c2ecehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DBTIU3ZNBFWZ56V4X7JIAD33V5H2GOMC/vendor-advisoryx_refsource_FEDORA