Message Editing Flaw in Matrix SDK UI Affects User Security
CVE-2026-45057

4.9MEDIUM

Key Information:

Vendor

Matrix-org

Status
Matrix-sdk-ui
Vendor
CVE Published:
11 September 2026

What is CVE-2026-45057?

A vulnerability in the matrix-sdk-ui crate prior to version 0.17.0 stems from insufficient validation during message editing processes. Specifically, the implementation allows for replacement of encrypted events without requiring the replacement event to be encrypted, which could let a malicious administrator or impersonator forge messages to appear as if they were sent by a legitimate user. This loophole undermines the integrity of user communications. The matrix-sdk-ui 0.17.0 update rectifies this flaw by aligning the edit process with the established security protocols for encrypted messages as per the Matrix specification. Users are encouraged to upgrade to the latest version to mitigate this risk.

Affected Version(s)

matrix-sdk-ui < 0.16.1

References

https://github.com/matrix-org/matrix-rust-sdk/security/ad...
x_refsource_CONFIRM
https://github.com/matrix-org/matrix-rust-sdk/pull/6454
x_refsource_MISC
https://github.com/matrix-org/matrix-rust-sdk/releases/ta...
x_refsource_MISC

CVSS V3.1

Score:
4.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
High
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.