CVE-2026-21876
- Source
- https://cve.org/CVERecord?id=CVE-2026-21876
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-21876.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-21876
- Aliases
-
- GHSA-36fv-25j3-r2c5
- Downstream
- Published
- 2026-01-08T13:55:37.102Z
- Modified
- 2026-07-15T01:49:06.713055131Z
- Severity
-
- 9.3 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N CVSS Calculator
- Summary
- OWASP CRS has multipart bypass using multiple content-type parts
- Details
-
The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 4.22.0 and 3.3.8, the current rule 922110 has a bug when processing multipart requests with multiple parts. When the first rule in a chain iterates over a collection (like
MULTIPART_PART_HEADERS), the capture variables (TX:0,TX:1) get overwritten with each iteration. Only the last captured value is available to the chained rule, which means malicious charsets in earlier parts can be missed if a later part has a legitimate charset. Versions 4.22.0 and 3.3.8 patch the issue. - Database specific
{ "cna_assigner": "GitHub_M", "cwe_ids": [ "CWE-794" ], "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21876.json" }- References
-
- https://github.com/coreruleset/coreruleset/releases/tag/v3.3.8
- https://github.com/coreruleset/coreruleset/releases/tag/v4.22.0
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21876.json
- https://github.com/coreruleset/coreruleset/security/advisories/GHSA-36fv-25j3-r2c5
- https://nvd.nist.gov/vuln/detail/CVE-2026-21876
- https://github.com/coreruleset/coreruleset/commit/80d80473abf71bd49bf6d3c1ab221e3c74e4eb83
- https://github.com/coreruleset/coreruleset/commit/9917985de09a6cf38b3261faf9105e909d67a7d6
- https://github.com/daytriftnewgen/CVE-2026-21876
Affected packages
Git / github.com/coreruleset/coreruleset
Affected ranges
- Type
- GIT
- Repo
- https://github.com/coreruleset/coreruleset
- Events
-
Introduced0 Unknown introduced commit / All previous commits are affectedFixedIntroducedFixedFixedFixed
- Database specific
{ "source": [ "CPE_RANGE", "REFERENCES" ], "cpe": "cpe:2.3:a:owasp:owasp_modsecurity_core_rule_set:*:*:*:*:*:*:*:*", "extracted_events": [ { "introduced": "0" }, { "fixed": "3.3.8" }, { "introduced": "4.0.0" }, { "fixed": "4.22.0" } ] }
Affected versions
Other
nightly
v2.*
v2.2.5
v2.2.6
v2.2.7
v3.*
v3.0.0-rc1
v3.0.0-rc2
v3.0.0-rc3
v3.0.1
v3.1.0-rc1
v3.2-rc1
v3.2.0-rc1
v3.3.0
v3.3.0-rc1
v3.3.0-rc2
v3.3.1-rc1
v3.3.2
v3.3.3
v3.3.4
v3.3.5
v3.3.6
v3.3.7
v4.*
v4.0.0
v4.1.0
v4.10.0
v4.11.0
v4.12.0
v4.13.0
v4.14.0
v4.15.0
v4.16.0
v4.17.0
v4.17.1
v4.18.0
v4.19.0
v4.2.0
v4.20.0
v4.21.0
v4.3.0
v4.4.0
v4.5.0
v4.6.0
v4.7.0
v4.8.0
v4.9.0