CVE-2026-107825

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, ProcessURI in internal/corazawaf/transaction.go handles a url.ParseRequestURI failure by retaining the raw URI but leaving QUERY_STRING, ARGS_GET, ARGS_GET_NAMES, and the GET-derived portion of ARGS empty. An unauthenticated attacker can place control bytes in a URI passed directly by integrations such as coraza-spoa, coraza-proxy-wasm, custom FFI hosts, or WASM hosts, causing Coraza to omit query parameters that the downstream integration may still process and allowing rules targeting those variables to be bypassed. The bundled coraza/v3/http integration is not affected because Go net/http rejects such malformed request targets before calling Coraza. This issue is fixed in version 3.8.0.

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, ProcessURI in internal/corazawaf/transaction.go handles a url.ParseRequestURI failure by retaining the raw URI but leaving QUERY_STRING, ARGS_GET, ARGS_GET_NAMES, and the GET-derived portion of ARGS empty. An unauthenticated attacker can place control bytes in a URI passed directly by integrations such as coraza-spoa, coraza-proxy-wasm, custom FFI hosts, or WASM hosts, causing Coraza to omit query parameters that the downstream integration may still process and allowing rules targeting those variables to be bypassed. The bundled coraza/v3/http integration is not affected because Go net/http rejects such malformed request targets before calling Coraza. This issue is fixed in version 3.8.0.

Root Cause

File: internal/corazawaf/transaction.go, lines 834–866.

parsedURL, err := url.ParseRequestURI(uri)
query := ""
if err != nil {
    tx.variables.urlencodedError.Set(err.Error())
    path = uri
    tx.variables.requestURI.Set(uri)
    /*
        tx.Variables.VARIABLE_URI_PARSE_ERROR.Set("1")
        posRawQuery := strings.Index(uri, "?")
        if posRawQuery != -1 {
            tx.ExtractArguments("GET", uri[posRawQuery+1:])
            path = uri[:posRawQuery]
            query = uri[posRawQuery+1:]
        } else {
            path = uri
        }
        tx.Variables.RequestUri.Set(uri)
    */
} else {
    tx.ExtractGetArguments(parsedURL.RawQuery)   // only path that populates ARGS_GET
    tx.variables.requestURI.Set(parsedURL.String())
    path = parsedURL.Path
    query = parsedURL.RawQuery
}
...
tx.variables.queryString.Set(query)

When url.ParseRequestURI(uri) returns an error — which Go's stdlib does for any URI containing raw control bytes (\x00, \n, \r, \t, other 0x00–0x1F, 0x7F) — the error branch silently produces an empty QUERY_STRING and an empty ARGS_GET collection. The fallback logic that should split on ? and populate the GET arguments from the raw tail is already present in the source as a commented-out block, referencing a VARIABLE_URI_PARSE_ERROR variable that was never wired up.

Consequences on the error branch:

• ARGS_GET / ARGS_GET_NAMES / ARGS (union) are empty — ExtractGetArguments is never called.
• QUERY_STRING is empty (initial query := "" at line 835 persists through to queryString.Set(query) at line 866).
• REQUEST_FILENAME / REQUEST_BASENAME contain the entire URI including any ?… query suffix (because path = uri at line 838 bypasses the parse, and the subsequent strings.LastIndexAny(path, "/\\") runs over the raw URI).
• URLENCODED_ERROR is set to the Go error message. That variable is also set by the urlencoded body processor on body-decode failures, so an operator cannot distinguish "malformed URI" from "malformed request body" without string-matching the error text.
• REQUEST_URI_RAW (set unconditionally at line 822, before the parse) is populated correctly.

Any rule targeting ARGS_GET, ARGS, ARGS_NAMES, ARGS_GET_NAMES, or QUERY_STRING — which is the default target set for the vast majority of OWASP CRS GET-side signature rules — does not fire against attacker content that reaches Coraza via a URI Go's net/url rejects.

Reachability

This issue does not affect the standard coraza/v3/http + net/http integration. Go's http.ReadRequest calls url.ParseRequestURI first and rejects malformed URIs with 400 Bad Request before ProcessURI is invoked. Verified experimentally against a Coraza-wrapped net/http server — a raw request with a control-byte-laced URI produced HTTP 400, and the handler was never reached.

The bug is reachable when an integration forwards raw URI bytes to tx.ProcessURI directly, bypassing Go's HTTP parser:

• coraza-spoa — HAProxy SPOP agent. Receives URI from HAProxy, which permits bytes net/http rejects.
• coraza-proxy-wasm — Envoy WASM filter. Passes the :path pseudo-header from Envoy.
• Custom FFI/WASM hosts and any embedder calling tx.ProcessURI(rawURI, method, httpVersion) with bytes not pre-validated by Go's URL parser.

This gates the attack to Attack Complexity:High — a standard Go HTTP deployment is not exposed.

Proof of Concept

Direct-API reproduction (simulating the non-net/http integration path):

waf, _ := coraza.NewWAF(coraza.NewWAFConfig().WithDirectives(`
SecRuleEngine On
SecRule ARGS_GET     "@contains ATTACK_HERE_XYZ" "id:9001,phase:1,deny,status:403"
SecRule QUERY_STRING "@contains ATTACK_HERE_XYZ" "id:9002,phase:1,deny,status:403"
`))

for _, uri := range []string{
    "/search?q=ATTACK_HERE_XYZ",                    // baseline
    "/search?q=ATTACK_HERE_XYZ\x00&y=1",       …

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, ProcessURI in internal/corazawaf/transaction.go handles a url.ParseRequestURI failure by retaining the raw URI but leaving QUERY_STRING, ARGS_GET, ARGS_GET_NAMES, and the GET-derived portion of ARGS empty. An unauthenticated attacker can place control bytes in a URI passed directly by integrations such as coraza-spoa, coraza-proxy-wasm, custom FFI hosts, or WASM hosts, causing Coraza to omit query parameters that the downstream integration may still process and allowing rules targeting those variables to be bypassed. The bundled coraza/v3/http integration is not affected because Go net/http rejects such malformed request targets before calling Coraza. This issue is fixed in version 3.8.0.

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, ProcessURI in internal/corazawaf/transaction.go handles a url.ParseRequestURI failure by retaining the raw URI but leaving QUERY_STRING, ARGS_GET, ARGS_GET_NAMES, and the GET-derived portion of ARGS empty. An unauthenticated attacker can place control bytes in a URI passed directly by integrations such as coraza-spoa, coraza-proxy-wasm, custom FFI hosts, or WASM hosts, causing Coraza to omit query parameters that the downstream integration may still process and allowing rules targeting those variables to be bypassed. The bundled coraza/v3/http integration is not affected because Go net/http rejects such malformed request targets before calling Coraza. This issue is fixed in version 3.8.0.

Root Cause

File: internal/corazawaf/transaction.go, lines 834–866.

parsedURL, err := url.ParseRequestURI(uri)
query := ""
if err != nil {
    tx.variables.urlencodedError.Set(err.Error())
    path = uri
    tx.variables.requestURI.Set(uri)
    /*
        tx.Variables.VARIABLE_URI_PARSE_ERROR.Set("1")
        posRawQuery := strings.Index(uri, "?")
        if posRawQuery != -1 {
            tx.ExtractArguments("GET", uri[posRawQuery+1:])
            path = uri[:posRawQuery]
            query = uri[posRawQuery+1:]
        } else {
            path = uri
        }
        tx.Variables.RequestUri.Set(uri)
    */
} else {
    tx.ExtractGetArguments(parsedURL.RawQuery)   // only path that populates ARGS_GET
    tx.variables.requestURI.Set(parsedURL.String())
    path = parsedURL.Path
    query = parsedURL.RawQuery
}
...
tx.variables.queryString.Set(query)

When url.ParseRequestURI(uri) returns an error — which Go's stdlib does for any URI containing raw control bytes (\x00, \n, \r, \t, other 0x00–0x1F, 0x7F) — the error branch silently produces an empty QUERY_STRING and an empty ARGS_GET collection. The fallback logic that should split on ? and populate the GET arguments from the raw tail is already present in the source as a commented-out block, referencing a VARIABLE_URI_PARSE_ERROR variable that was never wired up.

Consequences on the error branch:

• ARGS_GET / ARGS_GET_NAMES / ARGS (union) are empty — ExtractGetArguments is never called.
• QUERY_STRING is empty (initial query := "" at line 835 persists through to queryString.Set(query) at line 866).
• REQUEST_FILENAME / REQUEST_BASENAME contain the entire URI including any ?… query suffix (because path = uri at line 838 bypasses the parse, and the subsequent strings.LastIndexAny(path, "/\\") runs over the raw URI).
• URLENCODED_ERROR is set to the Go error message. That variable is also set by the urlencoded body processor on body-decode failures, so an operator cannot distinguish "malformed URI" from "malformed request body" without string-matching the error text.
• REQUEST_URI_RAW (set unconditionally at line 822, before the parse) is populated correctly.

Any rule targeting ARGS_GET, ARGS, ARGS_NAMES, ARGS_GET_NAMES, or QUERY_STRING — which is the default target set for the vast majority of OWASP CRS GET-side signature rules — does not fire against attacker content that reaches Coraza via a URI Go's net/url rejects.

Reachability

This issue does not affect the standard coraza/v3/http + net/http integration. Go's http.ReadRequest calls url.ParseRequestURI first and rejects malformed URIs with 400 Bad Request before ProcessURI is invoked. Verified experimentally against a Coraza-wrapped net/http server — a raw request with a control-byte-laced URI produced HTTP 400, and the handler was never reached.

The bug is reachable when an integration forwards raw URI bytes to tx.ProcessURI directly, bypassing Go's HTTP parser:

• coraza-spoa — HAProxy SPOP agent. Receives URI from HAProxy, which permits bytes net/http rejects.
• coraza-proxy-wasm — Envoy WASM filter. Passes the :path pseudo-header from Envoy.
• Custom FFI/WASM hosts and any embedder calling tx.ProcessURI(rawURI, method, httpVersion) with bytes not pre-validated by Go's URL parser.

This gates the attack to Attack Complexity:High — a standard Go HTTP deployment is not exposed.

Proof of Concept

Direct-API reproduction (simulating the non-net/http integration path):

waf, _ := coraza.NewWAF(coraza.NewWAFConfig().WithDirectives(`
SecRuleEngine On
SecRule ARGS_GET     "@contains ATTACK_HERE_XYZ" "id:9001,phase:1,deny,status:403"
SecRule QUERY_STRING "@contains ATTACK_HERE_XYZ" "id:9002,phase:1,deny,status:403"
`))

for _, uri := range []string{
    "/search?q=ATTACK_HERE_XYZ",                    // baseline
    "/search?q=ATTACK_HERE_XYZ\x00&y=1",       …

Coraza: ProcessURI silently drops QUERY_STRING and ARGS_GET on URI parse failure — defense-in-depth bypass for non-net/http integrations in github.com/corazawaf/coraza