CyberSecBulletin
CVE-2025-68435NVD status: Analyzed

zerobyte: Authentication Bypass by Primary Weakness

Published Updated By the CyberSecBulletin desk

CVE-2025-68435 is a critical-severity authentication bypass by primary weakness vulnerability in zerobyte from Nicotsx, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected zerobyte versions: < 0.18.5. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.41% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Check which version of zerobyte you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
Nicotsxzerobyte< 0.18.5Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (github.com).

Official description

Zerobyte is a backup automation tool Zerobyte versions prior to 0.18.5 and 0.19.0 contain an authentication bypass vulnerability where authentication middleware is not properly applied to API endpoints. This results in certain API endpoints being accessible without valid session credentials. This is dangerous for those who have exposed Zerobyte to be used outside of their internal network. A fix has been applied in both version 0.19.0 and 0.18.5. If immediate upgrade is not possible, restrict network access to the Zerobyte instance to trusted networks only using firewall rules or network segmentation. This is only a temporary mitigation; upgrading is strongly recommended.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Authentication Bypass by Primary Weakness

The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.

More Authentication Bypass by Primary Weakness vulnerabilities (CWE-305)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other references

Recent Authentication Bypass by Primary Weakness vulnerabilities

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