Vulnerability-Lookup

CVE-2026-41504 (GCVE-0-2026-41504)

Vulnerability from cvelistv5 – Published: 2026-10-12 19:59 – Updated: 2026-10-13 17:26

Title

OWASP Coraza WAF: Native audit-log format allows CRLF injection and log forgery via request body and header fields

Summary

OWASP Coraza WAF is a golang modsecurity compatible web application firewall library. From 3.0.0 until 3.8.0, the Native audit-log formatter in internal/auditlog/formats.go writes attacker-influenced request and response fields without neutralizing carriage returns or line feeds. When SecAuditLogFormat Native is enabled, injected line breaks can create forged lines inside a transaction record. An attacker who controls request or response body, header, error-message, or matched-rule data can inject carriage returns and line feeds that appear as forged audit lines within a transaction record. The forged content can mislead operators and line-oriented SIEM processing, although the unpredictable transaction boundary prevents straightforward impersonation of a separate complete session. This issue is fixed in version 3.8.0.

Severity

5.8 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-13 17:25 UTC

CWE

CWE-93 - Improper Neutralization of CRLF Sequences ('CRLF Injection')
CWE-117 - Improper Output Neutralization for Logs

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7752 records in the last 180 days details

References

3 references

URL	Tags
https://github.com/corazawaf/coraza/security/advi…	x_refsource_CONFIRM
https://github.com/corazawaf/coraza/commit/a30793…	x_refsource_MISC
https://github.com/corazawaf/coraza/releases/tag/v3.8.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
corazawaf	coraza	Affected: >= 3.0.0, < 3.8.0	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-41504

Vulnerability from fkie_nvd - Published: 2026-10-12 21:17 - Updated: 2026-10-13 18:17

Severity

5.8 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/corazawaf/coraza/commit/a3079325547c7c1e08522aed4d6468f25d080e25
	security-advisories@github.com	https://github.com/corazawaf/coraza/releases/tag/v3.8.0
	security-advisories@github.com	https://github.com/corazawaf/coraza/security/advisories/GHSA-prpw-wwv7-xjjr
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/corazawaf/coraza/security/advisories/GHSA-prpw-wwv7-xjjr

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "coraza",
          "vendor": "corazawaf",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.8.0"
            }
          ]
        }
      ],
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    }
  ],
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    {
      "lang": "en",
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    }
  ],
  "id": "CVE-2026-41504",
  "lastModified": "2026-10-13T18:17:23.983",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.8,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
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    }
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}

GHSA-PRPW-WWV7-XJJR

Vulnerability from github – Published: 2026-10-06 20:37 – Updated: 2026-10-06 20:37

Summary

Coraza: Native audit-log format allows CRLF injection and log forgery via request body and header fields

Details

Root Cause

File: internal/auditlog/formats.go — multiple sites write attacker-influenced bytes into the Native audit-log stream without escaping \r or \n:

// Part B — request headers (lines 72–80)
for k, vv := range al.Transaction().Request().Headers() {
    for _, v := range vv {
        res.WriteByte('\n')
        res.WriteString(k)
        res.WriteString(": ")
        res.WriteString(v)   // ← raw
    }
}

// Part C — request body (lines 85–86)
if body := al.Transaction().Request().Body(); body != "" {
    res.WriteString(body)    // ← raw
    res.WriteByte('\n')
}

// Part E — response body (lines 93–94)      raw
// Part F — response headers (lines 111–118) raw
// Part H — error messages (line 125)        raw
// Part K — matched-rule raw data (line 151)  raw

The Native format's section structure is line-based: sections are delimited by lines of the form --<10-char-random-prefix>-<Part>--, and line-based log parsers / SIEM rules rely on that structure. Any attacker-controlled bytes containing \n break the structural invariant and allow the attacker to inject lines that look like genuine audit content.

The other two Native-format implementations in Coraza are not affected: the JSON formatter (formats_json.go) and the OCSF formatter both round-trip values through json.Marshal, which escapes \r and \n.

Impact

An attacker who can land bytes into any of the listed audit-log fields can inject arbitrary lines — including lines that visually resemble new log entries — into the audit log file of a defender running the default SecAuditLogFormat Native configuration. Realistic consequences:

Forging entries to shift attribution. An injected line such as [client "9.9.9.9"] Coraza: Warning. ... sits alongside genuine matches in Part H, and a human operator (or simple SIEM rule) reading the log cannot tell them apart.
Confusing SIEM correlation. Any ingestion pipeline that splits on --...-[A-Z]-- boundaries or on [client "..."] patterns without validating the session prefix will treat the forged lines as separate records.
Breaking log-parsing tooling. Grep/awk pipelines, log tailers, and log-rotation tools with line-based assumptions can be poisoned with crafted binary sequences.
Hiding genuine incidents. An attacker who can also trigger a rule match on the same transaction (trivial — send any request that matches any audit-logged rule) can bury the real match under noise they control.

The forged lines cannot trivially impersonate an entire separate session: the 10-char random prefix in the real boundaries (boundaryPrefix := "--" + utils.RandomString(10) + "-", line 42) is not predictable from outside, and each transaction uses a fresh prefix. But the integrity of a single record is fully compromised, which is enough for the SIEM-confusion and attribution-shifting attacks.

Proof of Concept

Server with coraza.conf-recommended-style defaults:

SecRuleEngine On
SecAuditEngine On
SecAuditLogParts ABCFHZ
SecAuditLogType Serial
SecAuditLog /tmp/audit.log
SecAuditLogFormat Native
SecRequestBodyAccess On
SecRule REQUEST_METHOD "@rx ." \
    "id:1001,phase:1,pass,log,auditlog,msg:'trigger'"

Body vector — reachable via stock `coraza/v3/http` + `net/http`

Send an ordinary urlencoded POST whose body contains raw CRLF sequences and forged boundaries:

POST / HTTP/1.1
Content-Type: application/x-www-form-urlencoded

evil=benign\r\n--coraza-forged-X--\r\nForgedLine: yes\r\n--coraza-forged-H--\r\n[client "9.9.9.9"] FAKE ATTACK ENTRY

Resulting audit.log:

--heLNtylvjY-C--
evil=benign
--coraza-forged-X--
ForgedLine: yes
--coraza-forged-H--
[client "9.9.9.9"] FAKE ATTACK ENTRY

--heLNtylvjY-F--

The forged --coraza-forged-X-- / --coraza-forged-H-- boundaries and the spoofed [client "9.9.9.9"] line are structurally indistinguishable from the surrounding genuine log content. No rule fires, no error is raised, the attack is invisible to the WAF.

Header vector — reachable via non-net/http integrations only

The same effect applies to Part B (request headers) and Part F (response headers) when a header value contains raw \r\n. Go's net/http rejects such headers at parse time (400 Bad Request), so the stock HTTP wrapper is safe from this path; the vector is reachable when Coraza is called with header values that were not validated by net/http:

coraza-spoa (HAProxy SPOP agent) forwards headers from HAProxy, which has more permissive validation.
coraza-proxy-wasm / Envoy WASM hosts forward header values from the upstream proxy.
Custom FFI/WASM hosts and any embedder calling tx.AddRequestHeader(k, v) with unvalidated bytes.

Other raw-write sites (Part E response body, Part H error messages, Part K matched-rule data) share the same class of issue and should be fixed together.

Mitigation

Escape \r and \n at every raw-write site in internal/auditlog/formats.go. A single package-level helper is sufficient:

var logEscaper = strings.NewReplacer("\r", "\\r", "\n", "\\n")

// Part B — header values:
res.WriteString(logEscaper.Replace(v))

// Part F — header values: same
// Part H — error messages:
res.WriteString(logEscaper.Replace(alWithErrMsg.ErrorMessage()))
// Part K — matched-rule raw data:
res.WriteString(logEscaper.Replace(alEntry.Data().Raw()))

For Part C / Part E (bodies), the choice is policy-dependent:

Escape inline (logEscaper.Replace(body)): keeps the log human-readable for text bodies but loses fidelity for binary.
Base64 / hex-encode the whole part: binary-safe, matches the spirit of ModSecurity v2's binary-log handling, but less human-readable.

Escaping is the minimum; base64 for bodies is the more conservative default and is a reasonable audit-log-default change.

Additional defensive measure

Consider lengthening the boundaryPrefix random suffix from 10 chars to ≥16 chars (line 42). This strictly raises the bar for attackers attempting to fully forge a separate-looking session (not just inject lines into the current one). Low-cost change; narrows future variants of this bug class.

Affected versions

The Native formatter has been present since v3.0.0 (file existed at the first-release commit). All releases >= 3.0.0, <= 3.7.0 are affected when SecAuditLogFormat Native is used with SecAuditLogType Serial or SecAuditLogType Concurrent.

Unaffected:

Deployments using SecAuditLogFormat JSON (formats_json.go uses json.Marshal which escapes \r\n).
Deployments using OCSF output.
Deployments with SecAuditEngine Off.

References

internal/auditlog/formats.go lines 42, 72–80 (Part B), 85–88 (Part C), 93–96 (Part E), 111–118 (Part F), 125 (Part H), 151 (Part K)
coraza.conf-recommended — default SecAuditLogFormat Native, SecAuditLogParts ABIJDEFHZ / ABCFHZ variants
CWE-117 — Improper Output Neutralization for Logs
CWE-93 — CRLF Injection

Severity

5.8 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.7.0"
      },
      "package": {
        "ecosystem": "Go",
        "name": "github.com/corazawaf/coraza/v3"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.8.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41504"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-117",
      "CWE-93"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-06T20:37:27Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Root Cause\n\nFile: `internal/auditlog/formats.go` \u2014 multiple sites write attacker-influenced bytes into the Native audit-log stream without escaping `\\r` or `\\n`:\n\n```go\n// Part B \u2014 request headers (lines 72\u201380)\nfor k, vv := range al.Transaction().Request().Headers() {\n    for _, v := range vv {\n        res.WriteByte(\u0027\\n\u0027)\n        res.WriteString(k)\n        res.WriteString(\": \")\n        res.WriteString(v)   // \u2190 raw\n    }\n}\n\n// Part C \u2014 request body (lines 85\u201386)\nif body := al.Transaction().Request().Body(); body != \"\" {\n    res.WriteString(body)    // \u2190 raw\n    res.WriteByte(\u0027\\n\u0027)\n}\n\n// Part E \u2014 response body (lines 93\u201394)      raw\n// Part F \u2014 response headers (lines 111\u2013118) raw\n// Part H \u2014 error messages (line 125)        raw\n// Part K \u2014 matched-rule raw data (line 151)  raw\n```\n\nThe Native format\u0027s section structure is line-based: sections are delimited by lines of the form `--\u003c10-char-random-prefix\u003e-\u003cPart\u003e--`, and line-based log parsers / SIEM rules rely on that structure. Any attacker-controlled bytes containing `\\n` break the structural invariant and allow the attacker to inject lines that look like genuine audit content.\n\nThe other two Native-format implementations in Coraza are not affected: the JSON formatter (`formats_json.go`) and the OCSF formatter both round-trip values through `json.Marshal`, which escapes `\\r` and `\\n`.\n\n## Impact\n\nAn attacker who can land bytes into any of the listed audit-log fields can inject arbitrary lines \u2014 including lines that visually resemble new log entries \u2014 into the audit log file of a defender running the default `SecAuditLogFormat Native` configuration. Realistic consequences:\n\n- **Forging entries to shift attribution.** An injected line such as `[client \"9.9.9.9\"] Coraza: Warning. ...` sits alongside genuine matches in Part H, and a human operator (or simple SIEM rule) reading the log cannot tell them apart.\n- **Confusing SIEM correlation.** Any ingestion pipeline that splits on `--...-[A-Z]--` boundaries or on `[client \"...\"]` patterns without validating the session prefix will treat the forged lines as separate records.\n- **Breaking log-parsing tooling.** Grep/awk pipelines, log tailers, and log-rotation tools with line-based assumptions can be poisoned with crafted binary sequences.\n- **Hiding genuine incidents.** An attacker who can also trigger a rule match on the same transaction (trivial \u2014 send any request that matches *any* audit-logged rule) can bury the real match under noise they control.\n\nThe forged lines cannot trivially impersonate an entire *separate* session: the 10-char random prefix in the real boundaries (`boundaryPrefix := \"--\" + utils.RandomString(10) + \"-\"`, line 42) is not predictable from outside, and each transaction uses a fresh prefix. But the integrity of a *single* record is fully compromised, which is enough for the SIEM-confusion and attribution-shifting attacks.\n\n## Proof of Concept\n\nServer with `coraza.conf-recommended`-style defaults:\n\n```conf\nSecRuleEngine On\nSecAuditEngine On\nSecAuditLogParts ABCFHZ\nSecAuditLogType Serial\nSecAuditLog /tmp/audit.log\nSecAuditLogFormat Native\nSecRequestBodyAccess On\nSecRule REQUEST_METHOD \"@rx .\" \\\n    \"id:1001,phase:1,pass,log,auditlog,msg:\u0027trigger\u0027\"\n```\n\n### Body vector \u2014 reachable via stock `coraza/v3/http` + `net/http`\n\nSend an ordinary urlencoded POST whose body contains raw CRLF sequences and forged boundaries:\n\n```\nPOST / HTTP/1.1\nContent-Type: application/x-www-form-urlencoded\n\nevil=benign\\r\\n--coraza-forged-X--\\r\\nForgedLine: yes\\r\\n--coraza-forged-H--\\r\\n[client \"9.9.9.9\"] FAKE ATTACK ENTRY\n```\n\nResulting audit.log:\n\n```\n--heLNtylvjY-C--\nevil=benign\n--coraza-forged-X--\nForgedLine: yes\n--coraza-forged-H--\n[client \"9.9.9.9\"] FAKE ATTACK ENTRY\n\n--heLNtylvjY-F--\n```\n\nThe forged `--coraza-forged-X--` / `--coraza-forged-H--` boundaries and the spoofed `[client \"9.9.9.9\"]` line are structurally indistinguishable from the surrounding genuine log content. No rule fires, no error is raised, the attack is invisible to the WAF.\n\n### Header vector \u2014 reachable via non-net/http integrations only\n\nThe same effect applies to Part B (request headers) and Part F (response headers) when a header value contains raw `\\r\\n`. Go\u0027s `net/http` rejects such headers at parse time (`400 Bad Request`), so the stock HTTP wrapper is safe from this path; the vector is reachable when Coraza is called with header values that were not validated by `net/http`:\n\n- `coraza-spoa` (HAProxy SPOP agent) forwards headers from HAProxy, which has more permissive validation.\n- `coraza-proxy-wasm` / Envoy WASM hosts forward header values from the upstream proxy.\n- Custom FFI/WASM hosts and any embedder calling `tx.AddRequestHeader(k, v)` with unvalidated bytes.\n\nOther raw-write sites (Part E response body, Part H error messages, Part K matched-rule data) share the same class of issue and should be fixed together.\n\n## Mitigation\n\nEscape `\\r` and `\\n` at every raw-write site in `internal/auditlog/formats.go`. A single package-level helper is sufficient:\n\n```go\nvar logEscaper = strings.NewReplacer(\"\\r\", \"\\\\r\", \"\\n\", \"\\\\n\")\n\n// Part B \u2014 header values:\nres.WriteString(logEscaper.Replace(v))\n\n// Part F \u2014 header values: same\n// Part H \u2014 error messages:\nres.WriteString(logEscaper.Replace(alWithErrMsg.ErrorMessage()))\n// Part K \u2014 matched-rule raw data:\nres.WriteString(logEscaper.Replace(alEntry.Data().Raw()))\n```\n\nFor Part C / Part E (bodies), the choice is policy-dependent:\n\n- **Escape inline** (`logEscaper.Replace(body)`): keeps the log human-readable for text bodies but loses fidelity for binary.\n- **Base64 / hex-encode** the whole part: binary-safe, matches the spirit of ModSecurity v2\u0027s binary-log handling, but less human-readable.\n\nEscaping is the minimum; base64 for bodies is the more conservative default and is a reasonable audit-log-default change.\n\n### Additional defensive measure\n\nConsider lengthening the `boundaryPrefix` random suffix from 10 chars to \u226516 chars (line 42). This strictly raises the bar for attackers attempting to *fully* forge a separate-looking session (not just inject lines into the current one). Low-cost change; narrows future variants of this bug class.\n\n## Affected versions\n\nThe Native formatter has been present since `v3.0.0` (file existed at the first-release commit). All releases `\u003e= 3.0.0, \u003c= 3.7.0` are affected when `SecAuditLogFormat Native` is used with `SecAuditLogType Serial` or `SecAuditLogType Concurrent`.\n\n**Unaffected:**\n\n- Deployments using `SecAuditLogFormat JSON` (`formats_json.go` uses `json.Marshal` which escapes `\\r\\n`).\n- Deployments using OCSF output.\n- Deployments with `SecAuditEngine Off`.\n\n## References\n\n- `internal/auditlog/formats.go` lines 42, 72\u201380 (Part B), 85\u201388 (Part C), 93\u201396 (Part E), 111\u2013118 (Part F), 125 (Part H), 151 (Part K)\n- `coraza.conf-recommended` \u2014 default `SecAuditLogFormat Native`, `SecAuditLogParts ABIJDEFHZ` / `ABCFHZ` variants\n- CWE-117 \u2014 Improper Output Neutralization for Logs\n- CWE-93 \u2014 CRLF Injection",
  "id": "GHSA-prpw-wwv7-xjjr",
  "modified": "2026-10-06T20:37:27Z",
  "published": "2026-10-06T20:37:27Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/corazawaf/coraza/security/advisories/GHSA-prpw-wwv7-xjjr"
    },
    {
      "type": "WEB",
      "url": "https://github.com/corazawaf/coraza/commit/a3079325547c7c1e08522aed4d6468f25d080e25"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/corazawaf/coraza"
    },
    {
      "type": "WEB",
      "url": "https://github.com/corazawaf/coraza/releases/tag/v3.8.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Coraza: Native audit-log format allows CRLF injection and log forgery via request body and header fields"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-41504 (GCVE-0-2026-41504)

FKIE_CVE-2026-41504

GHSA-PRPW-WWV7-XJJR

Root Cause

Impact

Proof of Concept

Body vector — reachable via stock coraza/v3/http + net/http

Header vector — reachable via non-net/http integrations only

Mitigation

Additional defensive measure

Affected versions

References

Tags

Sightings

Nomenclature

Vulnerability timeline

Related by attack behaviour

Body vector — reachable via stock `coraza/v3/http` + `net/http`