CVE-2026-75514 BunkerWeb: rDNS bypass via missing forward-confirmation (FCrDNS) in blacklist, greylist, and antibot
Attackers can bypass BunkerWeb's blacklist, greylist, and antibot protections by spoofing reverse DNS records without forward confirmation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-75514?
CVE-2026-75514 is a medium-severity vulnerability in bunkerity bunkerweb, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-350
Which versions are affected by CVE-2026-75514?
How do I fix CVE-2026-75514?
No fix has been published for CVE-2026-75514 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-75514 being exploited?
There is no known exploitation of CVE-2026-75514 in the wild and no public exploit code.
Sources
Also known as GHSA-q54j-5484-pvjm.