RUSTSEC-2025-0041Published

matrix-sdk-crypto vulnerable to sender of encrypted events being spoofed by homeserver administrator

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2025-48937

Published

matrix-rust-sdk is an implementation of a Matrix client-server library in Rust. matrix-sdk-crypto since version 0.8.0 and up to 0.11.0 does not correctly validate the sender of an encrypted event. Accordingly, a malicious homeserver operator can modify events served to clients, making those events appear to the recipient as if they were sent by another user. This vulnerability is fixed in 0.11.1 and 0.12.0.

Source published: 10 Jun 2025 15:32:00 UTC
Source modified: 10 Jun 2025 15:46:22 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

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CVSS 3.1 · 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

euvd · EUVD-2025-17711

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Jun 10, 2025, 3:32:00 PM

dateUpdated: Jun 10, 2025, 3:46:22 PM

1 related source bulletins · separate from aliases

openSUSE-SU-2025:15218-1: fractal-11.2-1.1 on GA media

CVE-2025-48937

Source published: Jun 10, 2025, 3:32:00 PM (timezone not stated)
Source modified: Jun 10, 2025, 3:46:22 PM (timezone not stated)
Observed here: 9 Nov 2026 03:06:25 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

nvd · CVE-2025-48937

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-290

Original publisher date fields

published: 2025-06-10T16:15:41.670

lastModified: 2026-06-17T09:30:30.947

Source published: 10 Jun 2025 16:15:41 UTC
Source modified: 17 Jun 2026 09:30:30 UTC
Observed here: 25 Oct 2026 02:25:01 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

osv · GHSA-x958-rvg6-956w

Published

### Summary matrix-sdk-crypto since version 0.8.0 up to 0.11.0 does not correctly validate the sender of an encrypted event. Accordingly, a malicious homeserver operator can modify events served to clients, making those events appear to the recipient as if they were sent by another user. Although the CVSS score is 4.9 (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N), we consider this a High Severity security issue. ### Details The Matrix specification [requires](https://spec.matrix.org/v1.14/client-server-api/#mmegolmv1aes-sha2) that clients ensure that "the event’s `sender`, `room_id`, and the recorded `session_id` match a trusted session". The vulnerable matrix-sdk-crypto versions check that the `room_id` matches that of the session denoted by `session_id`, but do not check the `sender`. ### Patches The issue is resolved by [13c1d20](https://github.com/matrix-org/matrix-rust-sdk/commit/13c1d2048286bbabf5e7bc6b015aafee98f04d55), included in versions 0.11.1 and 0.12.0 of matrix-sdk-crypto. ### Workarounds Since a successful attack requires administrator access to the homeserver, users who trust the administrators of their local homeserver are not affected. ### References * https://spec.matrix.org/v1.14/client-server-api/#mmegolmv1aes-sha2

Source published: 10 Jun 2025 20:15:37 UTC
Source modified: 12 Jun 2025 21:23:37 UTC
Observed here: 24 Oct 2026 13:19:54 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

Publisher rating · MODERATE

osv · RUSTSEC-2025-0041

Published

matrix-sdk-crypto versions 0.8.0 up to and including 0.11.0 does not correctly validate the sender of an encrypted event. Accordingly, a malicious homeserver operator can modify events served to clients, making those events appear to the recipient as if they were sent by another user. Although the CVSS score is 4.9 (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N), we consider this a High severity security issue.

Source published: 11 Jun 2025 12:00:00 UTC
Source modified: 12 Oct 2026 18:00:10 UTC
Observed here: 24 Oct 2026 13:19:54 UTC
Source terms: OSV · upstream source license applies

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N