Is CVE-2026-24515 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-24515 being exploited in the wild.

How severe is CVE-2026-24515?

Low severity, with a CVSS score of 2.9, published 23 January 2026.

Which products and versions are affected?

Libexpat Project Expat versions before 2.7.4; Siemens RUGGEDCOM RST2428P all versions before V4.0; Siemens SINEC OS versions before V4.0.

Is there a fix for CVE-2026-24515?

A patch was published on 2026-01-31: libexpat 2.7.4 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-24515 attacked?

It is attacked with local access, in a software library.

Am I affected by CVE-2026-24515?

Check whether you run Libexpat Project Expat, Libexpat Project Libexpat, Siemens RUGGEDCOM RST2428P or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-24515: libexpat NULL pointer dereference in XML_ExternalEntityParserCreate

CVE-2026-24515 · Severity: low · CVSS 2.9 · Published 2026-01-23

libexpat is a widely used software library for parsing XML data, integrated into many operating systems and industrial products like Siemens RUGGEDCOM switches. A flaw in how the library handles specific data encoding settings could lead to a program crash. This primarily impacts the reliability and availability of applications that process untrusted XML files.

Technologies: Libexpat Project Expat, Libexpat Project Libexpat, Siemens RUGGEDCOM RST2428P, Siemens SINEC OS. Vendors: Libexpat Project, Siemens.

Quick answers

Is CVE-2026-24515 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-24515 being exploited in the wild.
How severe is CVE-2026-24515?: Low severity, with a CVSS score of 2.9, published 23 January 2026.
Which products and versions are affected?: Libexpat Project Expat versions before 2.7.4; Siemens RUGGEDCOM RST2428P all versions before V4.0; Siemens SINEC OS versions before V4.0.
Is there a fix for CVE-2026-24515?: A patch was published on 2026-01-31: libexpat 2.7.4 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-24515 attacked?: It is attacked with local access, in a software library.
Am I affected by CVE-2026-24515?: Check whether you run Libexpat Project Expat, Libexpat Project Libexpat, Siemens RUGGEDCOM RST2428P or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A vulnerability exists in libexpat's XML_ExternalEntityParserCreate function where it fails to properly copy user data associated with unknown encoding handlers when creating an external entity parser. This flaw can lead to a NULL pointer dereference (CWE-476) during XML processing. An attacker with the ability to provide specially crafted XML content to an application using libexpat could trigger a denial-of-service (crash). The attack vector is local and requires high complexity to exploit. The issue is resolved in libexpat version 2.7.4 and Siemens SINEC OS V4.0.

Affected products

libexpat project libexpat versions before 2.7.4
Siemens SINEC OS versions before V4.0
Siemens RUGGEDCOM RST2428P all versions before V4.0

Timeline

2026-01-19: other: Issue reported and fix developed in libexpat GitHub repository
2026-01-23: disclosed: CVE-2026-24515 assigned and published
2026-01-31: patched: libexpat 2.7.4 released
2026-06-02: advisory: Siemens published advisory SSA-253495 regarding SINEC OS products

References

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