libxml2: Use After Free
CVE-2024-56171 is a critical-severity use after free vulnerability in libxml2 from Xmlsoft, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 2.12.10, 2.13.6 as the first without the flaw, so updating libxml2 to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.18% chance of exploitation within 30 days, higher than 68% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update libxml2 to 2.12.10 or 2.13.6, whichever matches your release line, or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Xmlsoft | libxml2 | before 2.12.10; 2.13.0 up to, but not including, 2.13.6 | 2.12.10, 2.13.6 |
| NetApp | Hci Compute Node | Not specified in the record | Not stated |
| NetApp | H410c Firmware | Not specified in the record | Not stated |
| NetApp | H300s Firmware | Not specified in the record | Not stated |
| NetApp | H500s Firmware | Not specified in the record | Not stated |
| NetApp | H700s Firmware | Not specified in the record | Not stated |
| NetApp | H410s Firmware | Not specified in the record | Not stated |
| NetApp | Active Iq Unified Manager | Not specified in the record | Not stated |
| NetApp | Manageability Software Development Kit | Not specified in the record | Not stated |
| NetApp | Ontap | 9 | Not stated |
| NetApp | Solidfire & Hci Management Node | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA (mitre.org) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
libxml2 before 2.12.10 and 2.13.x before 2.13.6 has a use-after-free in xmlSchemaIDCFillNodeTables and xmlSchemaBubbleIDCNodeTables in xmlschemas.c. To exploit this, a crafted XML document must be validated against an XML schema with certain identity constraints, or a crafted XML schema must be used.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- security.netapp.com/advisory/ntap-20250328-0010/Third Party Advisory
Other references
- gitlab.gnome.org/GNOME/libxml2/-/issues/828Issue Tracking
- seclists.org/fulldisclosure/2025/Apr/10
- seclists.org/fulldisclosure/2025/Apr/11
- seclists.org/fulldisclosure/2025/Apr/12
- seclists.org/fulldisclosure/2025/Apr/13
- seclists.org/fulldisclosure/2025/Apr/4
- seclists.org/fulldisclosure/2025/Apr/5
- seclists.org/fulldisclosure/2025/Apr/8
- seclists.org/fulldisclosure/2025/Apr/9
- lists.debian.org/debian-lts-announce/2025/02/msg00028.html
Other vulnerabilities in libxml2
- 7.8 High severity
- 7.3 High severity
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 8.1 High severity
- 8.8 High severity
- 7.8 High severity
- 7.4 High severity
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