CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2026-73857
High (7.5) in owasp-modsecurity modsecurity. EPSS 0.4% estimated probability of exploitation activity in the next 30 days.
On this page
ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.15 until 3.0.17, XML request body processing with SecParseXmlIntoArgs set to On or OnlyArgs can leave XMLNodes::parsing_ctx_arg uninitialized in the SAX end-element callback. A single crafted unauthenticated HTTP request can make a worker dereference the pointer, resulting in a constant-value write to an attacker-controlled address. The resulting memory corruption can terminate the worker and may disclose memory or redirect execution. Earlier 3.0.x releases and ModSecurity 2.x do not use the affected path. This issue is fixed in version 3.0.17.
Severity
- EPSS
- 0.4% estimated probability of exploitation activity in the next 30 days; 35th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-10. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Not in the NVD yet
- Record from
- the CVE List, synced
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Explain CVE-2026-73857 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-73857?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-73857?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-73857 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| owasp-modsecurity ModSecurity | >= 3.0.15, < 3.0.17 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12, 13, 14 | modsecurity | no fix listed | DEBIAN-CVE-2026-73857 |
| Ubuntu | 20.04:LTS, 22.04:LTS, 24.04:LTS and 2 more | modsecurity | no fix listed | UBUNTU-CVE-2026-73857 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.