CVE catalog
CVE-2021-42717
modsecurity: CVE-2021-42717
- Severity
- High · CVSS 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 3.25% · Oct 25, 2026
ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects. Crafted JSON objects with nesting tens-of-thousands deep could result in the web server being unable to service legitimate requests. Even a moderately large (e.g., 300KB) HTTP request can occupy one of the limited NGINX worker processes for minutes and consume almost all of the available CPU on the machine. Modsecurity 2 is similarly vulnerable: the affected versions include 2.8.0 through 2.9.4.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | modsecurity | sid | 3.0.16-1 | fixed |
| Debian | modsecurity | forky | 3.0.16-1 | fixed |
| Debian | modsecurity | trixie | 3.0.14-1+deb13u1 | fixed |
| Debian | modsecurity | bookworm | 3.0.9-1+deb12u2 | fixed |
| Debian | modsecurity-apache | sid | 2.9.13-1 | fixed |
| Debian | modsecurity-apache | forky | 2.9.13-1 | fixed |
| Debian | modsecurity-apache | trixie | 2.9.11-1+deb13u1 | fixed |
| Debian | modsecurity-apache | bookworm | 2.9.7-1+deb12u2 | fixed |
| Debian | modsecurity-apache | bookworm-security | 2.9.7-1+deb12u1 | fixed |
| Ubuntu | modsecurity-apache | pro | 2.9.3-3 | vulnerable |
| Ubuntu | modsecurity-apache | pro | 2.9.5-1 | vulnerable |
| Ubuntu | modsecurity-apache | pro | 2.9.5-1ubuntu0.1~esm1 | fixed |
| Ubuntu | modsecurity-apache | 20.04 | 2.9.3-1 | vulnerable |
| Ubuntu | modsecurity-apache | 20.04 | 2.9.3-1ubuntu0.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | modsecurity | source | sid | 3.0.6-1 | not yet assigned | Not reported | Not reported |
| Debian | modsecurity | source | forky | 3.0.6-1 | not yet assigned | Not reported | Not reported |
| Debian | modsecurity | source | trixie | 3.0.6-1 | not yet assigned | Not reported | Not reported |
| Debian | modsecurity | source | bookworm | 3.0.6-1 | not yet assigned | Not reported | Not reported |
| Debian | modsecurity-apache | source | sid | 2.9.5-1 | not yet assigned | Not reported | Not reported |
| Debian | modsecurity-apache | source | forky | 2.9.5-1 | not yet assigned | Not reported | Not reported |
| Debian | modsecurity-apache | source | trixie | 2.9.5-1 | not yet assigned | Not reported | Not reported |
| Debian | modsecurity-apache | source | bookworm | 2.9.5-1 | not yet assigned | Not reported | Not reported |
| Ubuntu | modsecurity-apache | deb | pro | 2.9.5-1ubuntu0.1~esm1 | Not reported | USN-6370-1 | Not reported |
| Ubuntu | modsecurity-apache | deb | 20.04 | 2.9.3-1ubuntu0.1 | Not reported | USN-6370-1 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libapache2-mod-security2]Fixed
Source package: [modsecurity-apache]
Details (4)
2.9.7-1+deb12u2· amd64 · bookwormFixed · Fixed:
2.9.5-1dsa · modsecurity-apache · debian · bookworm; dsa · modsecurity-apache · debian · 12
2.9.7-1+deb12u2· arm64 · bookwormFixed · Fixed:
2.9.5-1dsa · modsecurity-apache · debian · bookworm; dsa · modsecurity-apache · debian · 12
2.9.7-1+deb12u1· amd64 · bookworm-securityFixed · Fixed:
2.9.5-1dsa · modsecurity-apache · debian · bookworm; dsa · modsecurity-apache · debian · 12
2.9.7-1+deb12u1· arm64 · bookworm-securityFixed · Fixed:
2.9.5-1dsa · modsecurity-apache · debian · bookworm; dsa · modsecurity-apache · debian · 12
- [libmodsecurity3]Fixed
Source package: [modsecurity]
Details (2)
3.0.9-1+deb12u2· amd64 · bookwormFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · bookworm; dsa · modsecurity · debian · 12
3.0.9-1+deb12u2· arm64 · bookwormFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · bookworm; dsa · modsecurity · debian · 12
- [libmodsecurity-dev]Fixed
Source package: [modsecurity]
Details (2)
3.0.9-1+deb12u2· amd64 · bookwormFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · bookworm; dsa · modsecurity · debian · 12
3.0.9-1+deb12u2· arm64 · bookwormFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · bookworm; dsa · modsecurity · debian · 12
[Debian 13 (Trixie)]
- [libapache2-mod-security2]Fixed
Source package: [modsecurity-apache]
Details (2)
2.9.11-1+deb13u1· amd64 · trixieFixed · Fixed:
2.9.5-1dsa · modsecurity-apache · debian · 13
2.9.11-1+deb13u1· arm64 · trixieFixed · Fixed:
2.9.5-1dsa · modsecurity-apache · debian · 13
- [libmodsecurity3t64]Fixed
Source package: [modsecurity]
Details (2)
3.0.14-1+deb13u1· amd64 · trixieFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · 13
3.0.14-1+deb13u1· arm64 · trixieFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · 13
- [libmodsecurity-dev]Fixed
Source package: [modsecurity]
Details (2)
3.0.14-1+deb13u1· amd64 · trixieFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · 13
3.0.14-1+deb13u1· arm64 · trixieFixed · Fixed:
3.0.6-1dsa · modsecurity · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2023_0257-1.json]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2021-42717]
- [https://osv.dev/vulnerability/DLA-3031-1]
- [https://osv.dev/vulnerability/DSA-5023-1]
- [https://osv.dev/vulnerability/USN-6370-1]
- [https://security-tracker.debian.org/tracker/CVE-2021-42717]
- [https://wid.cert-bund.de/.well-known/csaf/white/2022/wid-sec-w-2022-0302.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [SUSE security advisories and VEX]