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CVE-2026-53643

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 allow low-privileged st

FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 allow low-privileged staff accounts to perform unauthorized actions via admin API endpoints. The root cause is a combination of the can_always_access module flag (which grants all staff access to certain modules) and insufficient permission checks or unsafe parameter handling on individual endpoints.

Version 0.8.0 contains a fix. Some workarounds are available. Restrict staff accounts to only those who need access to sensitive settings and/or use a reverse proxy or WAF to restrict access to the affected endpoints to trusted IP addresses or higher-privilege roles.

EPSS 0.00226
EPSS exploitation odds0.23% · top 86%
Monitor
  • ⚠ NVD has not scored this CVE yet - manual triage required (common for recent CVEs)
No Sigma yet — build one → YARA rules0
Look this up elsewhere - one-click external pivots
NVDCVE.orgCISAExploit-DBGitHub PoCVulnCheck KEVGreyNoise
▸ How to read a CVE - triage first, then detect and patch
This page is every public fact about CVE-2026-53643, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.
Triage: should I act now? Four signals, and they are not interchangeable:
CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.
How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.
Then what - two workflows:
Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.
Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).
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Severity & exploitation scoring

EPSS exploitation probability
0.23%
Top 86%odds of exploitation in the next 30 days
CVSS metric silhouette
No structured CVSS vector for this CVE. Older entries often have only a numeric base score - the metric breakdown radar requires a full AV:_/AC:_/... vector string published by NVD.
SSVC triage
No SSVC vulnrichment for this CVE. CISA's Vulnrichment program scores newer CVEs (~2024 onwards) plus selected older critical ones. Use the EPSS probability + KEV status to triage instead.
Attack path
Full kill chain
→
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ATT&CK techniques

20

Techniques this CVE enables. Pills with a solid outline are high confidence - named directly in ATT&CK or Nuclei, or human-curated by CTID; the rest are inferred from the weakness type using MITRE's CVE Mapping Methodology and the CWE → CAPEC chain. Broad, generic-weakness guesses are filtered out. A small N× marks a technique that N independent sources agree on.

T1007 · System Service Discovery T1016 · System Network Configuration Discovery T1018 · Remote System Discovery T1033 · System Owner/User Discovery T1036.005 · Match Legitimate Resource Name or Location T1046 · Network Service Discovery T1049 · System Network Connections Discovery T1057 · Process Discovery T1069 · Permission Groups Discovery T1082 · System Information Discovery T1083 · File and Directory Discovery T1087 · Account Discovery T1111 · Multi-Factor Authentication Interception T1120 · Peripheral Device Discovery T1124 · System Time Discovery T1134.001 · Token Impersonation/Theft T1135 · Network Share Discovery T1211 · Exploitation for Stealth T1217 · Browser Information Discovery T1542.002 · Component Firmware
▤ Build a SIEM detection for these techniques
▤

CAPEC attack patterns

12

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-116 · Excavation CAPEC-CAPEC-13 · Subverting Environment Variable Values CAPEC-CAPEC-169 · Footprinting CAPEC-CAPEC-22 · Exploiting Trust in Client CAPEC-CAPEC-224 · Fingerprinting CAPEC-CAPEC-285 · ICMP Echo Request Ping CAPEC-CAPEC-287 · TCP SYN Scan CAPEC-CAPEC-290 · Enumerate Mail Exchange (MX) Records CAPEC-CAPEC-291 · DNS Zone Transfers CAPEC-CAPEC-292 · Host Discovery CAPEC-CAPEC-293 · Traceroute Route Enumeration CAPEC-CAPEC-294 · ICMP Address Mask Request
⬡

Weakness Classification

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
CWE-639Authorization Bypass Through User-Controlled Key
CWE-862Missing Authorization
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Related CVEs

8
CVEs linked to this one by a shared weakness (CWE) or affected product - joins on data already in the engine, with the reason shown per row.
CVE-1999-0059 IRIX fam service allows an attacker to obtain a list of all files on the server. same CWE-200 HIGH CVE-1999-0524 ICMP information such as (1) netmask and (2) timestamp is allowed from arbitrary... same CWE-200 MEDIUM CVE-1999-1136 Vulnerability in Predictive on HP-UX 11.0 and earlier, and MPE/iX 5.5 and earlie... same CWE-200 CVE-1999-0453 An attacker can identify a CISCO device by sending a SYN packet to port 1999, wh... same CWE-200 CVE-2012-5571 A flaw was found in OpenStack Keystone. This vulnerability allows remote authent... same CWE-639 MEDIUM CVE-2014-8356 The web administrative portal in Zhone zNID 2426A before S3.0.501 allows remote ... 1 same CWE-639 HIGH CVE-2016-20033 Wowza Streaming Engine 4.5.0 contains a local privilege escalation vulnerability... same CWE-639 HIGH CVE-2017-0882 Multiple versions of GitLab expose sensitive user credentials when assigning a u... same CWE-639 MEDIUM
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References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-563q-g4r4-6f9m
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