VulnerabilityPublished 20 Sep 2022Updated 29 May 2025

CVE-2022-39958: OWASP ModSecurity Core Rule Set · Incorrect Authorization

Affects OWASP ModSecurity Core Rule SetSource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 3.2.0 or 3.1.0 soon.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.2% chance of exploitation in 30 days – higher than 68% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.2.0, 3.1.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Sep 2022
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade OWASP ModSecurity Core Rule Set to 3.2.0 or 3.1.0.

Affected software

Product	Affected	Fixed in
OWASP ModSecurity Core Rule Set	Affected >=3.0.0 <3.1.0 >=3.1.0 <3.2.0	Fixed in 3.1.0 3.2.0

AI-suggested

European organizations should immediately assess their use of OWASP ModSecurity CRS and identify if they are running affected versions (3.0.x, 3.1.x, 3.2.1, 3.3.2). The primary mitigation is to upgrade to the patched versions 3.2.2 or 3.3.3. Beyond upgrading, organizations should configure the CRS paranoia level to 3 or higher to improve detection of suspicious requests involving Range headers or other evasion techniques. It is advisable to implement strict monitoring and alerting on unusual HTTP Range header usage patterns, such as repeated small byte-range requests from the same source IP. Web server and application logs should be analyzed for anomalies consistent with incremental data exfiltration attempts. Network intrusion detection systems (NIDS) can be tuned to detect suspicious Range header usage. Additionally, organizations should review backend server configurations to limit or disable support for HTTP Range requests where feasible, or implement rate limiting on such requests to reduce the risk of sequential data leakage. Finally, regular security audits and penetration testing should include attempts to exploit this vulnerability to verify the effectiveness of mitigations.

Description

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. 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 and to configure a CRS paranoia level of 3 or higher.

Impact

For European organizations, this vulnerability poses a significant risk to the confidentiality of sensitive data protected by web application firewalls using the OWASP ModSecurity CRS. Many European enterprises, government agencies, and critical infrastructure providers deploy ModSecurity CRS as part of their web security stack. The ability to bypass WAF protections and exfiltrate data in small undetectable chunks could lead to leakage of intellectual property, personal data protected under GDPR, or other sensitive information. This could result in regulatory penalties, reputational damage, and financial losses. The incremental nature of the data exfiltration makes detection difficult, increasing the window of exposure. Organizations relying on legacy CRS versions or those who have not updated to the patched versions remain vulnerable. Additionally, the vulnerability could be leveraged in targeted attacks against high-value European targets, including financial institutions, healthcare providers, and government portals, where data confidentiality is paramount.

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Jul 2025, 03:11 UTC

WeaknessesCWE-863

Technical details

References

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