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HIGH

CVE-2022-39957

CVE-2022-39957 — Response body bypass in OWASP ModSecurity Core Rule Set via a specialy crafted charset in the HTTP Accept header

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. 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.

Published Updated Sources: cvelistV5, NCSC.ch

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

1%

chance of exploitation in 30 days

Affects

owasp

modsecurity_core_rule_set

CVSS base

7.3

HIGH

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

owasp

Products (1)

modsecurity core rule set

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
7.3CVSS 3.1HIGH——cvelistV5

Weakness & attack patterns

  • CWE-693

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1574.010Hijack Execution Flow: ServicesFile Permissions Weakness
  • T1083File and Directory Discovery
  • T1574.005Hijack Execution Flow: Executable Installer File Permissions Weakness

References

7 on the record

Elsewhere on this site

  • owaspevery CVE for this vendor
  • CWE-693other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.