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Fencer Intel
medium 5.9

CVE-2026-107833 json

OWASP Coraza WAF: Unbounded recursion in JSON response body processor causes CPU exhaustion

published last mo. modified 21d ago also EUVD-2026-95926 , GHSA-3c6w-j9xm-8h2h , GO-2026-6690

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, ProcessResponse in internal/bodyprocessors/json.go passes the ignoreJSONRecursionLimit value of -1 to readJSON, while the recursive guard only stops at zero. A network attacker who can cause an application protected by Coraza to return deeply nested JSON can make response-body processing perform quadratic work, consuming one CPU core for seconds per response within the default ResponseBodyLimit. Request JSON processing is not affected by this specific path because it uses the configured request recursion limit, and exploitation requires response-body inspection to be enabled. This issue is fixed in version 3.8.0.

Patch / fix

  • go github.com/corazawaf/coraza/v3 3.8.0
  • coraza coraza 3.8.0

Is CVE-2026-107833 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/corazawaf/coraza/security/advisories/GHSA-3c6w-j9xm-8h2h referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/corazawaf/coraza/v3
>=3.0.0, <3.8.0
3.8.0
go github.com/corazawaf/coraza
all versions
 no fix listed
go github.com/corazawaf/coraza/v2
all versions
 no fix listed

Affected products

  • corazawaf coraza

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.