GHSA-fmvh-rvq5-hhjx CVE-2018-16515 PYSEC-2026-845
Matrix Synapse Improper Signature Validation
- Severity
- 8.8 / 10
- High · CVSS 3.0
- Exploit chance (EPSS)
- 1.54%
- Chance of exploitation in the next 30 days. Higher than 74.89% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-347 Improper Verification of Cryptographic Signature
- Fix
0.33.3.1- Upgrade matrix-synapse to this version or later
Description
Matrix Synapse before 0.33.3.1 and 0.33.2.1 allows remote attackers to spoof events and possibly have unspecified other impacts by leveraging improper transaction and event signature validation.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| matrix-synapse | >= 0.33.3, < 0.33.3.1 |
0.33.3.1 |
| matrix-synapse | < 0.33.2.1 |
0.33.2.1 |
| matrix-synapse | < 0.33.2.1>= 0.33.3, < 0.33.3.1 |
0.33.2.10.33.3.1 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
matrix-synapse PyPI → 0.33.3.1
- pip
pip install --upgrade "matrix-synapse>=0.33.3.1"- poetry
poetry add "matrix-synapse>=0.33.3.1"- uv
uv add "matrix-synapse>=0.33.3.1"
Severity breakdown
CVSS 3.0 8.8
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-347: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
References
Advisories
Packages
Other links
- github.com/matrix-org/synapse/issues/3796
- github.com/matrix-org/synapse/commit/5bf8bc79ebc22c61968f2eb487714813fccbdb9b
- github.com/matrix-org/synapse/commit/804dd41e18c449e711e443398b95c9f6c68b6fa2
- github.com/matrix-org/synapse/commit/a5a0bf5cf71caed3c4e3677d2bce667c147dadfc
- github.com/matrix-org/synapse/commit/c127c8d0421f0228a46ebbe280c9537e8d8ea42b
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IRW7Y…
- matrix.org/blog/2018/09/06/critical-security-update-synapse-0-33-3-1
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-6qf2-7x63-mm6v Synapse pagination Denial of Service | Low | Also affects matrix-synapse |
| GHSA-8q93-326v-3m7g Synapse CPU starvation (Denial of Service) | Medium | Also affects matrix-synapse |
| GHSA-fh66-fcv5-jjfr Synapse's invalid device keys degrade federation functionality | Medium | Also affects matrix-synapse |
| GHSA-v56r-hwv5-mxg6 Synapse vulnerable to federation denial of service via malformed events | High | Also affects matrix-synapse |
| GHSA-56w4-5538-8v8h Synapse Matrix has a partial room state leak via Sliding Sync | Medium | Also affects matrix-synapse |
| GHSA-vp6v-whfm-rv3g Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders | Critical | Also affects matrix-synapse |
| GHSA-f3r3-h2mq-hx2h Synapse allows a a malformed invite to break the invitee's `/sync` | Medium | Also affects matrix-synapse |
| GHSA-rfq8-j7rh-8hf2 Synapse allows unsupported content types to lead to memory exhaustion | High | Also affects matrix-synapse |
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