Information Disclosure in FOSSBilling (CVE-2026-40495)
Summary
Vulnerability in FOSSBilling (CVE-2026-40495). Risk of unauthorized operations or information disclosure. Exploitable via hide_version_public.
Original description
The description as published by the source.
FOSSBilling is a free, open-source billing and client management system. Versions prior to 0.8.0 leak the exact system version through asset cache buster parameters in HTML output, bypassing the hide_version_public security setting. The FOSSBilling version is embedded in the query string of every and tag generated by the script_tag and stylesheet_tag Twig filters. This information is visible to all visitors — including unauthenticated guests — on every page, regardless of whether the hide_version_public setting is enabled. The X-FOSSBilling-Version HTTP header and the guest.system.version API endpoint correctly honour the hide_version_public setting, but the asset cache buster parameters were overlooked. Knowledge of the exact FOSSBilling version makes it significantly easier for malicious actors to identify known vulnerabilities applicable to a given installation and craft targeted exploits. While not a direct vulnerability on its own, it undermines the intended protection offered by the hide_version_public setting and facilitates reconnaissance. Version 0.8.0 contains a patch. There is no practical workaround that removes the version from asset URLs without modifying source code.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-40495 has been found in FOSSBilling.
Attackers can target a specific entry point like hide_version_public over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "FOSSBilling CVE-2026-40495" on the vendor's site.
CVE-2026-40495 (FOSSBilling) — CWE-200
Attack surface: hide_version_public / script_tag / stylesheet_tag / guest.system.version
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Information disclosure (CWE-200) exists in FOSSBilling. Attackers reach the vulnerable code path via hide_version_public.
Check the vendor advisory for the affected versions of FOSSBilling. Attack surface: hide_version_public / script_tag / stylesheet_tag / guest.system.version.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'FOSSBilling' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'FOSSBilling' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
FOSSBillingを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov
- web github.com