CVE-2026-70454
CVE-2026-70454 — rsync < 3.5.0 TLS Certificate Validation Bypass via SSL/OpenSSL Mode
rsync 3.2.0 through 3.2.3 (openssl mode) and rsync-ssl through 3.4.4 (stunnel mode) contain a TLS certificate validation vulnerability that allows on-path attackers to intercept encrypted sessions by presenting self-signed or otherwise invalid certificates. Attackers can exploit the failure to validate server TLS certificates against a trusted CA or verify certificate hostname matching to decrypt or tamper with rsync session content without detection by the client.
Published Updated Sources: NVD, RsyncProject (CNA), GitHub, SOCRadar CTI
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Unreported
no source claims exploitation
EPSS
0%
ahead of 0% of scored CVEs
CVSS base
8
high · 2 sources
Remediation
The vendor's own words where we have them.
Upgrade rsync to a fixed release (3.5.0). Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Prioritize based on EPSS, PoC availability, and external exposure.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| RsyncProject | rsync | 0 to <= 3.4.4 | Vulnerable |
| RsyncProject | rsync | 3.5.0 | Patched |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Availability
None
Confidentiality
High
Integrity
High
Scope
Changed
Attack Complexity
High
Attack Vector
Network
Privileges Req
None
User Interaction
Required
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 8 | CVSS 3.1 | high | 1.6 | 5.8 | VulnCheck (CNA), RsyncProject (CNA) |
| 7.6 | CVSS 4.0 | high | — | — | RsyncProject (CNA) |
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
What this weakness leads to
MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.
CWE-295 · Improper Certificate Validation
- Bypass Protection Mechanism
- Gain Privileges or Assume Identity::
Mitigation: Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
Weakness & attack patterns
- CWE-295
Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.
Detection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Prioritize edge telemetry for network-reachable rsync.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 8.0 (AV:N)
Aug 13, 2026 · NVD
Initial · CVE published
Aug 13, 2026 · NVD
References
3 on the record
- github.com/RsyncProject/rsync/releases/tag/v3.5.0
Exploit, Third Party Advisory, Mitre
- github.com/RsyncProject/rsync/security/advisories/GHSA-3c3x-ww2w-5r5p
Exploit, Third Party Advisory, Mitre
- www.vulncheck.com/advisories/rsync-tls-certificate-validation-bypass-via-ssl-openssl-mode
Vendor Advisory
Elsewhere on this site
- RsyncProjectevery CVE for this vendor
- Remote Code Execsame class
- CWE-295other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2026-70454 is rsync < 3.5.0 TLS Certificate Validation Bypass via SSL/OpenSSL Mode, a high vulnerability affecting rsync from RsyncProject. The current evidence does not list it in CISA KEV, and the exploit status is: Active exploitation is not confirmed from current sources for CVE-2026-70454. Public exploit evidence is: A public PoC is not confirmed from current sources for CVE-2026-70454. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 8 describes technical severity, while EPSS 0% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.