CVE
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.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 3.3.10, 4.25.1, 4.28.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 3.3.10, 4.25.1, 4.28.0.
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 24/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
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.
Read the original 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.
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.
Read the source excerpt
“Deployments serving APIs that accept XML and where ModSecurity's XML body parsing is enabled”
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.2/10CVSS 7.2
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
- Would score about 29 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 3.3.10, 4.25.1, 4.28.0.
Workaround: Add SecRuleUpdateTargetByTag directives for each attack tag with the XML://@* target in local configuration loaded after CRS.
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
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"}.Timeline
- CVE published
- First seen by cve.now
Affected versions
- coreruleset coreruleset
fixed in 3.3.10; fixed in 4.25.1; fixed in 4.28.0
Evidence 7
Vendor advisory · 1
Establishes: Affected and fixed versions.
- Advisory
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Other links · 4
- Repository
- Repository
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-62971
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: cve.now feed data
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: github.com
Which versions are affected by CVE-2026-62971?
coreruleset: before 3.3.10; before 4.25.1; before 4.28.0.Source: cve.now feed data
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: github.com
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: github.com