CVE-2022-39955
Partial rule set bypass in OWASP ModSecurity Core Rule Set by submitting a specially crafted HTTP Content-Type header
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
7.3
Partial rule set bypass in OWASP ModSecurity Core Rule Set by submitting a specially crafted HTTP Content-Type header
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Record
CVE-2022-39955- CVSS 3.1
- 7.3 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-863
- Updated
- 2026-11-02
EUVDEUVD-2022-42399
7.3
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Record
EUVD-2022-42399- CVSS 3.1
- 7.3 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-x6xv-j46p-v597
9.8
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting...
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Record
GHSA-x6xv-j46p-v597- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-863
- Updated
- 2026-11-02
NVD
7.3
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Record
CVE-2022-39955- CVSS 3.1
- 7.3 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-863
- Updated
- 2026-11-02
OSV
7.3
Partial rule set bypass in OWASP ModSecurity Core Rule Set by submitting a specially crafted HTTP Content-Type header
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Record
CVE-2022-39955- CVSS 3.1
- 7.3 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - Weakness
- CWE-863
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2022-39955
9.8
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Record
DEBIAN-CVE-2022-39955- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
OSVOESA-2022-1964
9.8
mod_security_crs security update
The base rules are provided for mod_security by this package.
Security Fix(es):
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.(CVE-2022-39955)
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass for HTTP multipart requests by submitting a payload that uses a character encoding scheme via the Content-Type or the deprecated Content-Transfer-Encoding multipart MIME header fields that will not be decoded and inspected by the web application firewall engine and the rule set. The multipart payload will therefore bypass detection. A vulnerable backend that supports these encoding schemes can potentially be exploited. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised upgrade to 3.2.2 and 3.3.3 respectively. The mitigation against these vulnerabilities depends on the installation of the latest ModSecurity version (v2.9.6 / v3.0.8).(CVE-2022-39956)
- Record
OESA-2022-1964- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2022-39955
7.3
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
- Record
UBUNTU-CVE-2022-39955- CVSS 3.1
- 7.3 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVMGASA-2024-0070 No score
Updated apache-mod_security-crs packages fix security vulnerabilities
A SQL injection bypass (aka PL1 bypass) exists in OWASP ModSecurity Core
Rule Set (owasp-modsecurity-crs) through v3.1.0-rc3 via {ab} where a
is a special function name (such as "if") and b is the SQL statement to
be executed. (CVE-2018-16384)
Modsecurity owasp-modsecurity-crs 3.2.0 (Paranoia level at PL1) has a
SQL injection bypass vulnerability. Attackers can use the comment
characters and variable assignments in the SQL syntax to bypass
Modsecurity WAF protection and implement SQL injection attacks on Web
applications. (CVE-2020-22669)
OWASP ModSecurity Core Rule Set 3.1.x before 3.1.2, 3.2.x before 3.2.1,
and 3.3.x before 3.3.2 is affected by a Request Body Bypass via a
trailing pathname. (CVE-2021-35368)
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule
set bypass by submitting a specially crafted HTTP Content-Type header
field that indicates multiple character encoding schemes. A vulnerable
back-end can potentially be exploited by declaring multiple Content-Type
"charset" names and therefore bypassing the configurable CRS
Content-Type header "charset" allow list. An encoded payload can bypass
CRS detection this way and may then be decoded by the backend.
(CVE-2022-39955)
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule
set bypass for HTTP multipart requests by submitting a payload that uses
a character encoding scheme via the Content-Type or the deprecated
Content-Transfer-Encoding multipart MIME header fields that will not be
decoded and inspected by the web application firewall engine and the
rule set. The multipart payload will therefore bypass detection. A
vulnerable backend that supports these encoding schemes can potentially
be exploited. (CVE-2022-39956)
The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body
bypass. A client can issue an HTTP Accept header field containing an
optional "charset" parameter in order to receive the response in an
encoded form. Depending on the "charset", this response can not be
decoded by the web application firewall. A restricted resource, access
to which would ordinarily be detected, may therefore bypass detection.
(CVE-2022-39957)
The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body
bypass to sequentially exfiltrate small and undetectable sections of
data by repeatedly submitting an HTTP Range header field with a small
byte range. A restricted resource, access to which would ordinarily be
detected, may be exfiltrated from the backend, despite being protected
by a web application firewall that uses CRS. Short subsections of a
restricted resource may bypass pattern matching techniques and allow
undetected access. (CVE-2022-39958)
- Record
MGASA-2024-0070- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
modsecurity-crsDebian:12 |
before 3.3.4-1 | 3.3.4-1 |
modsecurity-crsDebian:13 |
before 3.3.4-1 | 3.3.4-1 |
modsecurity-crsDebian:14 |
before 3.3.4-1 | 3.3.4-1 |
modsecurity-crsDebian:10 From an advisory covering 7 CVEs |
before 3.2.3-0+deb10u3, plus listed versions 3.1.0-13.1.0-1+deb10u13.1.0-1+deb10u23.1.1-13.2.0-1 |
3.2.3-0+deb10u3 |
modsecurity-crsDebian:11 From an advisory covering 5 CVEs |
before 3.3.4-1~deb11u1, plus listed versions 3.3.0-13.3.0-1+deb11u13.3.2-1 |
3.3.4-1~deb11u1 |
apache-mod_security-crsMageia:9 From an advisory covering 7 CVEs |
before 3.3.5-1.mga9 | 3.3.5-1.mga9 |
mod_security_crsopenEuler:20.03-LTS-SP1 From an advisory covering 2 CVEs |
before 3.2.2-1.oe1 | 3.2.2-1.oe1 |
mod_security_crsopenEuler:20.03-LTS-SP3 From an advisory covering 2 CVEs |
before 3.2.2-1.oe1 | 3.2.2-1.oe1 |
mod_security_crsopenEuler:22.03-LTS From an advisory covering 2 CVEs |
before 3.2.2-1.oe2203 | 3.2.2-1.oe2203 |
modsecurity-crsUbuntu:16.04:LTS |
All versions, plus listed versions 2.2.9-1 |
None known |
Show 7 moreShow less
| Package | Affected | Fixed |
|---|---|---|
modsecurity-crsUbuntu:18.04:LTS |
All versions, plus listed versions 3.0.0-33.0.2-1 |
None known |
modsecurity-crsUbuntu:20.04:LTS |
All versions, plus listed versions 3.1.1-13.2.0-1 |
None known |
modsecurity-crsUbuntu:22.04:LTS |
All versions, plus listed versions 3.3.0-13.3.2-1 |
None known |
modsecurity-crsUbuntu:24.04:LTS |
All versions, plus listed versions 3.3.5-13.3.5-2 |
None known |
modsecurity-crsUbuntu:25.10 |
All versions, plus listed versions 3.3.7-1 |
None known |
modsecurity-crsUbuntu:26.10 |
All versions, plus listed versions 3.3.8-13.3.9-1 |
None known |
modsecurity-crsUbuntu:26.04:LTS |
All versions, plus listed versions 3.3.7-13.3.8-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2022-39955 is a high vulnerability (CVSS 7.3) in Owasp Modsecurity Core Rule Set, published September 20, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.42%, the 72nd percentile. Fixed in modsecurity-crs 3.3.4-1.
References
coreruleset.org/20220919/crs-version-3-3-3-and-3-2-2-covering-several-cves
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PD56EAYNGB6E6QQH62LAYCONOP6OH5DZ
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YPQ6CCMX3MU4A7MTCGQJA7VMJW3IQDXV
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HL2L2GF7GOCWPMJZDUE5OXDSXHGG3XUJ
lists.debian.org/debian-lts-announce/2023/01/msg00033.html
security.gentoo.org/glsa/202305-25
Show 18 moreShow less
lists.debian.org/debian-lts-announce/2025/08/msg00004.html
nvd.nist.gov/vuln/detail/CVE-2022-39955
lists.fedoraproject.org/archives/list/[email protected]/message/HL2L2GF7GOCWPMJZDUE5OXDSXHGG3XUJ
lists.fedoraproject.org/archives/list/[email protected]/message/PD56EAYNGB6E6QQH62LAYCONOP6OH5DZ
lists.fedoraproject.org/archives/list/[email protected]/message/YPQ6CCMX3MU4A7MTCGQJA7VMJW3IQDXV
github.com/advisories/GHSA-x6xv-j46p-v597
github.com/CVEProject/cvelistV5/tree/main/cves/2022/39xxx/CVE-2022-39955.json
security-tracker.debian.org/tracker/CVE-2022-39955
advisories.mageia.org/MGASA-2024-0070.html
bugs.mageia.org/show_bug.cgi?id=30977
lists.fedoraproject.org/archives/list/[email protected]/thread/C4Q7DCCE37GT5ZBJOWP4NGUD4L3FAMDB
lists.fedoraproject.org/archives/list/[email protected]/thread/6MS5GMNYHFFIBWLJW7N3XAD24SLF3PFZ
coreruleset.org/20210630/cve-2021-35368-crs-request-body-bypass
debian.org/lts/security/2023/dla-3293
openeuler.org/en/security/safety-bulletin/detail.html?id=openEuler-SA-2022-1964
nvd.nist.gov/vuln/detail/CVE-2022-39956
ubuntu.com/security/CVE-2022-39955
cve.org/CVERecord?id=CVE-2022-39955