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Fencer Vulns
high 7.5

CVE-2026-42268 json

ModSecurity: Unsigned integer underflow in @verifySSN / @verifyCPF / @verifySVNR operators

published 2026-05-12 5 mo ago modified 2026-10-26 13 d ago also BIT-modsecurity-2026-42268 , BIT-modsecurity2-2026-42268 , EUVD-2026-29854 , GHSA-vwr3-7x7g-7p9w

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. From 3.0.0 to before 3.0.15, there is an unhandled exception (std::out_of_range) caused by unsigned integer underflow in libmodsecurity3 if the user (administrator) uses a rule any of @verifySSN, @verifyCPF, or @verifySVNR. This vulnerability is fixed in 3.0.15.

Patch / fix

  • bitnami modsecurity 3.0.15
  • bitnami modsecurity2 3.0.15
  • owasp libmodsecurity 3.0.15
  • owasp modsecurity 3.0.15
  • owasp owasp_modsecurity 3.0.15
  • trustwave modsecurity 3.0.15
  • modsecurity Debian 12 3.0.9-1+deb12u2
  • modsecurity Debian 13 3.0.14-1+deb13u1
  • modsecurity Debian 14 3.0.15-1

debian advisories DEBIAN-CVE-2026-42268

  • modsecurity openSUSE Tumbleweed 3.0.15-1.1

opensuse advisories openSUSE-SU-2026:10732-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-42268 updated cvss 4.9

mod_security: ModSecurity: Denial of Service via unsigned integer underflow in rule verification functions

  • Red Hat Enterprise Linux 8 mod_security, mod_security-mlogc Red Hat Enterprise Linux 9 mod_security, mod_security-mlogc
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-vwr3-7x7g-7p9w referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami modsecurity
>=3.0.0, <3.0.15
3.0.15
bitnami modsecurity2
>=3.0.0, <3.0.15
3.0.15

Affected products

  • owasp-modsecurity ModSecurity

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)
  • CWE-248 Uncaught Exception

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.