Summary
Froxlor DomainZones.add allows DNS zone-file RR injection via record/type fields
Froxlor's DomainZones.add API command accepts user-controlled DNS record and type values and later writes them into generated BIND zone files without rejecting line delimiters, tab characters, or zone-file comment delimiters.
The stronger variant is in record. An authenticated customer with DNS-zone permissions can submit a normal A record request where record is:
www\t60\tIN\tA\t6.6.6.6 ;\n@
with type=A and content=127.0.0.1. The current record flow trims/lower-cases/IDNA-encodes the value, but does not reject CR/LF/HTAB or semicolon. The real Froxlor\Dns\DnsEntry::__toString() sink renders it as:
www 60 in a 6.6.6.6 ;
@ 18000 IN A 127.0.0.1
BIND accepts the generated zone file:
named-checkzone example.com froxlor_dns_record_injected.zone
zone example.com/IN: loaded serial 2026060501
OK
named-compilezone -D confirms both records are parsed as real DNS RRs:
example.com. 18000 IN A 127.0.0.1
www.example.com. 60 IN A 6.6.6.6
zone example.com/IN: loaded serial 2026060501
OK
Affected code in 2.3.7:
- lib/Froxlor/Api/Commands/DomainZones.php:92-93 reads record/type from API params.
- lib/Froxlor/Api/Commands/DomainZones.php:122-136 trims/lower-cases/IDNA-encodes record without control-character rejection.
- lib/Froxlor/Api/Commands/DomainZones.php:157-160 hardens content only.
- lib/Froxlor/Api/Commands/DomainZones.php:314-321 and 347-357 store record/type/content into domain_dns_entries.
- lib/Froxlor/Dns/Dns.php:297 passes stored values to DnsEntry.
- lib/Froxlor/Dns/DnsEntry.php:83 concatenates record/type/content into a zone-file line.
There is also a related type-field variant because type is not allowlisted and domain_dns_entries.type is varchar(10). The value NS\tns.\n@\tA renders one submitted entry as multiple zone-file records.
Impact: authenticated customer with DNS-zone permissions can inject additional BIND resource-record lines into the generated zone file for a domain they can manage in Froxlor, bypassing Froxlor's DNS field-level validation. This is DNS zone integrity loss and possible DNS availability impact inside the caller's manageable zone.
Suggested remediation: allowlist DNS RR types, reject CR/LF/HTAB/control chars/spaces/semicolon in record and type, validate record as a DNS owner name while allowing intended cases such as @, *, *.label, _service._proto, _dmarc, and DKIM selectors. Add defense-in-depth in DnsEntry or the DNS serializer so CR/LF cannot reach generated zone lines.
Attribution: Yaohui Wang.
Impact
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
CVE-2026-54543 has a CVSS score of 5.4 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.3.8); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-54543? CVE-2026-54543 is a medium-severity improper input validation vulnerability in froxlor/froxlor (composer), affecting versions <= 2.3.7. It is fixed in 2.3.8. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- How severe is CVE-2026-54543? CVE-2026-54543 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of froxlor/froxlor are affected by CVE-2026-54543? froxlor/froxlor (composer) versions <= 2.3.7 is affected.
- Is there a fix for CVE-2026-54543? Yes. CVE-2026-54543 is fixed in 2.3.8. Upgrade to this version or later.
- Is CVE-2026-54543 exploitable, and should I be worried? Whether CVE-2026-54543 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-54543 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-54543? Upgrade
froxlor/froxlorto 2.3.8 or later.