CVE-2021-42258
BQE BillQuick Web Suite 2018 through 2021 before 22.0.9.1 allows SQL injection for unauthenticated remote code execution, as exploited in the wild in October 2021 for ransomware installation. SQL injection can, for example, use the txtID (aka username) parameter. Successful exploitation can include the ability to execute arbitrary code as MSSQLSERVER$ via xp_cmdshell.
- CVSS
- 9.8Criticalscored by CISA
- Exploited in the wild
- Yes, in CISA KEV since 3 Nov 2021CISA deadline for US federal agencies: 17 Nov 2021known use in ransomware campaigns
- EPSS
- 75.2%chance of exploitation in the next 30 daystop 0.5% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Not stated by the vendorno fixed release in the CVE record
- Published
- 22 Oct 2021analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
Products named in our analysis
- bqe:billquick_web_suite
Fix and mitigation
WAF and other mitigations
Can a WAF block it? Yes. The attack is delivered via an HTTP request parameter (txtID) that is vulnerable to SQL injection, which typically involves unusual SQL syntax that a WAF can detect and block without affecting normal users. A WAF rule can match SQL injection syntax in the txtID (username) parameter. No tracked WAF vendor has published a rule for this CVE yet, so you would write it yourself.
What a custom rule would match: SQL injection syntax in the txtID (username) parameter
Also consider: patch · custom WAF rule · parameterized queries · ORM
Based on an AI reading of the CVE description, and no vendor rule found yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 3 Nov 2021. Known use in ransomware campaigns.
- CISA due date
- 17 Nov 2021, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- Detection templates only, no public exploit found: 1 Metasploit module · 1 Nuclei template
- CISA SSVC
- exploitation active, automatable yes, technical impact totalAssessed by CISA 3 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Metasploit
- auxiliary/gather/billquick_txtid_sqliauxiliary, rank normal
Nuclei
- BillQuick Web Suite SQL Injectiondetection template, critical
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 22 Oct 2021Published
- 3 Nov 2021Added to CISA KEV (exploited in the wild)11 days later
- 17 Nov 2021CISA remediation due date (US federal agencies)14 days later
- 3 Feb 2025CISA SSVC assessment: exploitation active1,175 days (about 3 years) later
- 21 Oct 2025CVE record last updated260 days (about 9 months) later
- 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | NetworkReachable over the internet or any routable network. | Reachable over the internet or any routable network. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2021-42258 being exploited?
Yes. CVE-2021-42258 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2021-42258?
CVE-2021-42258 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2021-42258?
Not known from our data. No patch reference has been recorded for CVE-2021-42258, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2021-42258 affect?
CVE-2021-42258 affects bqe:billquick_web_suite. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
2 references in the CVE record, grouped by the tags the record gives them.
Other links (2)
- huntress.com /blog/threat-advisory-hackers-are-exploiting-a-vulnerability-in-popular-billing-
- cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-42258
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Metasploit Framework: exploit and scanner modules
- Nuclei templates: detection templates
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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