matrix-sdk-ui: Incomplete edit validation

Answer in brief

CVE-2026-45057 records a Medium severity vulnerability in matrix-sdk-ui: Incomplete edit validation. The current sources do not mark it as known exploited. The current feed maps matrix-org/matrix-sdk-ui (generic), matrix-sdk-ui (rust). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 14, 2026Source checked Sep 17, 2026First seen by HOL Jun 11, 2026Material review Sep 14, 2026

Upstream Advisory

Key facts

Risk: Medium
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps matrix-org/matrix-sdk-ui (generic), matrix-sdk-ui (rust). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
matrix-org/matrix-sdk-uigeneric	< 0.16.1	Not reported
matrix-sdk-uirust	<0.16.1	0.16.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for matrix-org/matrix-sdk-ui, matrix-sdk-ui.
Review the reported fix. Update matrix-sdk-ui to 0.16.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Jun 11, 2026

Sources and claim methodology

Upstream source description

matrix-sdk-ui provides GUI-centric utilities on top of matrix-rust-sdk. The message edit validation logic in the `matrix-sdk-ui` crate prior to 0.17.0 is missing a check: when replacing an encrypted event, the replacement event itself is not required to be encrypted. This enables a malicious homeserver administrators (or actors with equivalent power) to impersonate or spoof messages as if they were sent by a victim user. `matrix-sdk-ui` 0.17.0 fixes the message edit validation logic to align with the algorithm for replacement events[^1] described in the Matrix specification. No known workarounds are available.

Quoted source text, attributed separately from HOL analysis.