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highRemote Code Exec

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

Affects

RsyncProject

2 products listed

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.

VendorProductVersionsStatus
RsyncProjectrsync0 to <= 3.4.4Vulnerable
RsyncProjectrsync3.5.0Patched

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.

ScoreVersionSeverityExpl.ImpactSource
8CVSS 3.1high1.65.8VulnCheck (CNA), RsyncProject (CNA)
7.6CVSS 4.0highRsyncProject (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.

MITRE

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.

CAPEC-475 · Signature Spoofing by Improper ValidationCAPEC-459 · Creating a Rogue Certification Authority Certificate

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Prioritize edge telemetry for network-reachable rsync.
web/proxy/WAF logsapplication logsnetwork IDS/IPSEDR process telemetryhost service logs

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

  1. 2026
  2. Added · CVSS 3.1 8.0 (AV:N)

    Aug 13, 2026 · NVD

  3. Initial · CVE published

    Aug 13, 2026 · NVD

References

3 on the record

Elsewhere on this site

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.