Read the docs
TI-2026-52878 Aliases CVE-2026-75514

BunkerWeb: rDNS bypass via missing forward-confirmation (FCrDNS) in blacklist, greylist, and antibot

Priority LOW 27CWE-350Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

BunkerWeb is an open-source, next-generation Web Application Firewall. Prior to 1.6.13, the blacklist, greylist, and antibot modules in src/common/core/blacklist/blacklist.lua, src/common/core/greylist/greylist.lua, and src/common/core/antibot/antibot.lua trust PTR suffix matches in IGNORE_RDNS, GREYLIST_RDNS, and ANTIBOT_IGNORE_RDNS without using get_ips to confirm that the hostname resolves to the client address. An unauthenticated remote attacker who controls a PTR record can spoof a trusted suffix to bypass rDNS-based blacklisting, gain greylist treatment, or skip an antibot challenge. This issue is fixed in version 1.6.13.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00597 48th percentileScored 2026-11-07
Fix Fixed bunkerweb (bunkerity): 1.6.13

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
bunkeritybunkerwebbefore 1.6.131.6.13Patch availableCNA
  • bunkerweb Vendorbunkerity Affected before 1.6.13 Fixed in 1.6.13 Patch available CNA

Remediation

  • Fix · CNA bunkerweb (bunkerity) Fixed in 1.6.13

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-75514

References

Other 4

  • TI-2026-39541 Improper input validation in bunkerity bunkerweb CVSS 4.0MEDIUM 6.1
  • TI-2026-44177 bunkerweb: Read-only Web UI users can delete job cache files due to missing authorization on /cache/ routes CVSS 3.1MEDIUM 5.4
  • TI-2024-35727 Open Redirect Vulnerability in Loading Page in bunkerweb CVSS 4.0MEDIUM 5.1
  • TI-2025-07379 Bunker Web 1.6.2 - Uncontrolled external site redirect CVSS 4.0MEDIUM 4.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences