CVE-2026-52747: modsecurity · Prior to 3.0.16, the multipart/form-data request body parser in libmodsecurity silently removes embedded line breaks from non-file form-field values
Affects modsecuritySource GCVE Database
Not known to be exploited · CVSS 8.6 High · fixed in 3.0.16 : patch modsecurity soon.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.0.16
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 10 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10modsecuritypkg:deb/ubuntu/modsecurity?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSmodsecuritypkg:deb/ubuntu/modsecurity?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSmodsecuritypkg:deb/ubuntu/modsecurity?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSmodsecuritypkg:deb/ubuntu/modsecurity?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSmodsecuritypkg:deb/ubuntu/modsecurity?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade ModSecurity to version 3.0.16 or later, where this issue is fixed. No other mitigations are indicated by the vendor advisory.
Description
ModSecurity versions prior to 3.0.16 have a vulnerability in the multipart/form-data request body parser that causes embedded line breaks in non-file form-field values to be silently removed. This behavior causes a mismatch between ModSecurity and backend applications, potentially allowing payloads relying on line breaks to bypass security rules inspecting ARGS or ARGS_POST. The issue is fixed in version 3.0.16.
References
- ubuntu.com/security/CVE-2026-52747 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-52747 (opens in a new tab)
- github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-rcw9-2f5r-7p88 (opens in a new tab)
- github.com/owasp-modsecurity/ModSecurity/commit/875504c2758169c41be1ad2f0cc64d896b7815d7 (opens in a new tab)
- github.com/owasp-modsecurity/ModSecurity/releases/tag/v3.0.16 (opens in a new tab)