Vulnerability · Published Aug 20, 2026 · Assigned by GitHub_M

CVE-2026-75514BunkerWeb: rDNS bypass via missing forward-confirmation (FCrDNS) in blacklist, greylist, and antibot

Medium 5.9

In plain English

A medium-severity security flaw in bunkerweb from bunkerity. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities).

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.6%top 51.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
bunkerity	bunkerweb	< 1.6.13

Weakness: CWE-350 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

References

https://github.com/bunkerity/bunkerweb/security/advisories/GHSA-q54j-5484-pvjm x_refsource_CONFIRM
https://github.com/bunkerity/bunkerweb/pull/3710 x_refsource_MISC
https://github.com/bunkerity/bunkerweb/commit/1a97e5b3f977130a1b84507a9e1f703c8eec12eb x_refsource_MISC
https://github.com/bunkerity/bunkerweb/releases/tag/v1.6.13 x_refsource_MISC