Improper input validation in Apache Apisix

CVE-2022-25757

In Apache APISIX before 2.13.0, when decoding JSON with duplicate keys, lua-cjson will choose the last occurred value as the result. By passing a JSON with a duplicate key, the attacker can bypass the body_schema validation in the request-validation plugin. For example, `{"string_payload":"bad","string_payload":"good"}` can be used to hide the "bad" input. Systems satisfy three conditions below are affected by this attack: 1. use body_schema validation in the request-validation plugin 2. upstream application uses a special JSON library that chooses the first occurred value, like jsoniter or gojay 3. upstream application does not validate the input anymore. The fix in APISIX is to re-encode the validated JSON input back into the request body at the side of APISIX. Improper Input Validation vulnerability in __COMPONENT__ of Apache APISIX allows an attacker to __IMPACT__. This issue affects Apache APISIX Apache APISIX version 2.12.1 and prior versions.

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.025 (83.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2022-25757?
CVE-2022-25757 is a critical-severity vulnerability in Apache Apisix, classified under Improper Input Validation. CVSS score: 9.8/10. Published 2022-03-28.
How severe is CVE-2022-25757?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2022-25757 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.