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Fencer Vulns
medium 5.3

CVE-2019-25043 json

ModSecurity 3.x before 3.0.4 mishandles key-value pair parsing, as demonstrated by a "string index out of range" error and worker-process c…

published 2021-05-06 5 y ago modified 2026-06-17 4 mo ago also EUVD-2019-11493

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.2%
EPSS 1.2% chance of exploitation in 30 days, percentile 68%
public exploits
0
none known

Summary

ModSecurity 3.x before 3.0.4 mishandles key-value pair parsing, as demonstrated by a "string index out of range" error and worker-process crash for a "Cookie: =abc" header.

Patch / fix

  • owasp modsecurity 3.0.4
  • modsecurity Debian 14, Debian 13, Debian 12 3.0.4-1

debian advisories DEBIAN-CVE-2019-25043

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-2019-25043 updated cvss 7.5

libmodsecurity: crafted key-value pair can lead to DoS

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

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

Exploit prediction

1.22% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/SpiderLabs/ModSecurity/issues/2566 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-755 Improper Handling of Exceptional Conditions

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.