CVE-2026-45056

MEDIUMPre-NVD 6.96.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 86% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
6.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.9Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

matrix-sdk-crypto is a no-network-IO implementation of a state machine that handles end-to-end encryption for Matrix clients. Starting in version 0.12.0 and prior to version 0.17.0, the matrix-sdk-crypto crate was missing a check for the user ID when decrypting an Olm-encrypted event containing the sender_device_keys property. This could be exploited to forge an encrypted to-device event, but only if the attacker colludes with the homeserver operator. This issue is fixed in matrix-sdk-crypto 0.17.0. There are no known workarounds for the issue.

CVSS v3
6.9
EG Score
6.9(medium)
EG Risk
31(Track)
EG Risk 31/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity69% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
15%
KEV
Not listed

Published

June 4, 2026

Last Modified

September 14, 2026

Advisory Details (4)

Auto-updated Sep 11, 2026
Patch available. Sources: github, github_pr, github_release.
generic

RUSTSEC-2026-0159: matrix-sdk-crypto: Sender-binding gaps in to-device messages › RustSec Advisory Database

https://rustsec.org/advisories/RUSTSEC-2026-0159.html
github_release Patch Available

matrix-sdk 0.16.1

Patch available: matrix-org/matrix-rust-sdk matrix-sdk-0.16.1

https://github.com/matrix-org/matrix-rust-sdk/releases/tag/matrix-sdk-0.16.1
github_pr Patch Available

Check the user ID in the embedded device keys

Patch available: matrix-org/matrix-rust-sdk matrix-sdk-0.17.0 (PR #6553 merged 2026-05-08)

https://github.com/matrix-org/matrix-rust-sdk/pull/6553
github Patch Available

Sender-binding gaps in to-device messages allow for sender spoofing · Advisory · matrix-org/matrix-rust-sdk · GitHub

https://github.com/matrix-org/matrix-rust-sdk/security/advisories/GHSA-wfq4-36m3-9g42

Vendor Advisories for CVE-2026-45056(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
crates.io(1)
PackageVulnerable rangeFixed inDependents
matrix-sdk-crypto—0.16.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 12× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-17 19:31 UTCEPSS rescore
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-14 19:24 UTCEG score recompute
  6. 2026-09-14 18:28 UTCEG score recompute
  7. 2026-09-14 05:23 UTCEG score recompute
  8. 2026-09-13 16:47 UTCEPSS rescore
  9. 2026-09-12 15:01 UTCEPSS rescore
  10. 2026-09-11 23:11 UTCEG score recompute
  11. 2026-09-11 21:24 UTCEG score recompute▲ 6.90
  12. 2026-09-11 21:23 UTCMITRE cvelistV5CVSS v3 → 6.9 · CVSS v4 → 6.9
  13. 2026-07-31 05:26 UTCEG score recompute
  14. 2026-07-26 22:16 UTCEG score recompute
  15. 2026-07-23 03:16 UTCEG score recompute
  16. 2026-06-14 23:18 UTCEPSS rescore
  17. 2026-06-13 23:00 UTCEPSS rescore
  18. 2026-06-12 23:12 UTCEPSS rescore
  19. 2026-06-04 15:10 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-45056?
CVE-2026-45056 is a medium vulnerability published on June 4, 2026. matrix-sdk-crypto is a no-network-IO implementation of a state machine that handles end-to-end encryption for Matrix clients. Starting in version 0.12.0 and prior to version 0.17.0, the matrix-sdk-crypto crate was missing a check for the user ID when decrypting an Olm-encrypted event containing the…
When was CVE-2026-45056 disclosed?
CVE-2026-45056 was first published in the National Vulnerability Database on June 4, 2026, with the most recent update on September 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45056 actively exploited?
CVE-2026-45056 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 85.3% of all scored CVEs.
What is the CVSS score of CVE-2026-45056?
CVE-2026-45056 has a CVSS v3 base score of 6.9 (NVD).
How do I remediate CVE-2026-45056?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45056, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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