4.9

CVE-2026-45057: matrix-org matrix-sdk-ui

CVSS: 4.9v3.1MediumDeferred
AliasesGHSA-h97m-27fx-42rxRUSTSEC-2026-0158
Published 11-09-2026Last modified 14-09-2026
Open JSON

Vulnerability summary

CVE-2026-45057 is a medium (CVSS 4.9) vulnerability in matrix-org matrix-sdk-ui. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.2% of scored vulnerabilities.

Overall risk
20/100
0100
Low · default modelHow is this calculated?
CVSS score
4.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.23%
0%100%
Low · +0.08 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 11-09-2026
    PublishedVulnerability first disclosed.
  2. 14-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

+0.08 pp

From 0.15% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.23%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Crates.Io1 product
  • matrix-sdk-ui< 0.16.1 | ≥ 0.0.0-0, < 0.16.1
Matrix-org1 product

2 vendors · 2 products

References

6 links