# CVE-2025-39787: Linux Kernel Qualcomm MDT loader buffer over-read

Source: https://junglewise.ai/threats/cve-2025-39787-linux-kernel-qualcomm-mdt-loader-buffer-over-read  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-09-11. Updated: 2026-07-30  
License: CC BY 4.0 with a link back

CVE-2025-39787 · Severity: high · CVSS 7.8 · Published 2025-09-11

A vulnerability was identified in the Linux kernel's Qualcomm MDT loader, a component used to load firmware onto specialized hardware processors. The issue allows the system to read data beyond the intended boundaries of a firmware file header if the file is not properly formatted. An attacker with local access could potentially exploit this to cause a system crash or gain unauthorized access to sensitive information, impacting the reliability and security of industrial and mobile devices using these chips.

Technologies: [Linux Kernel](https://junglewise.ai/threats/technologies/kernel), [Siemens SIMATIC CN 4100](https://junglewise.ai/threats/technologies/simatic-cn-4100), [Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP](https://junglewise.ai/threats/technologies/simatic-s7-1500-cpu-1518-4-pn-dp-mfp), [Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP](https://junglewise.ai/threats/technologies/simatic-s7-1500-cpu-1518f-4-pn-dp-mfp), [Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP](https://junglewise.ai/threats/technologies/siplus-s7-1500-cpu-1518-4-pn-dp-mfp). Vendors: [Linux](https://junglewise.ai/threats/vendors/linux), [Siemens](https://junglewise.ai/threats/vendors/siemens).

## Quick answers

**Is CVE-2025-39787 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-39787 being exploited in the wild.

**How severe is CVE-2025-39787?** High severity, with a CVSS score of 7.8, published 11 September 2025.

**Which products and versions are affected?** Linux Kernel 4.11 to 5.4.297, 5.5 to 5.10.241, 5.11 to 5.15.190, 5.16 to 6.1.149, 6.2 to 6.6.103, 6.7 to 6.12.44, 6.13 to 6.16.4; Siemens SIMATIC CN 4100 before V5.0; Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5 and later; Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5 and later; and 1 more.

**Is there a fix for CVE-2025-39787?** A patch was published on 2025-08-28: Patch committed to Linux stable tree Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-39787 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2025-39787?** Check whether you run Linux Kernel, Siemens SIMATIC CN 4100, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP 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 the Qualcomm MDT loader (drivers/soc/qcom/mdt_loader.c) within the Linux kernel due to insufficient validation of ELF headers. While the remoteproc subsystem sanitizes headers, other clients of the MDT loader may not, leading to an out-of-bounds read when iterating over program or section headers. Specifically, the loader failed to verify that the firmware buffer was large enough to contain the ELF header and that the 'e_phentsize' and 'e_shentsize' fields matched expected structure sizes. An attacker with the ability to provide a malicious firmware file could trigger an out-of-bounds read, potentially leading to a kernel crash or memory disclosure. The issue has been resolved by implementing a new validation function, 'mdt_header_valid', which checks buffer bounds and header integrity before processing.

## Affected products

- Linux Linux Kernel 2aad40d911ee to 0d59ce2bfc3b, 1096eb63ecfc, 43d26997d88c, 81278be4eb5f, 87bfabb3b2f4, 981c845f2983, 9f9967fed9d0, e1720eb32acf
- Siemens SIMATIC CN 4100 before V5.0
- Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5 and later
- Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5 and later
- Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5 and later

## Timeline

- 2025-08-28: patched: Patch committed to Linux stable tree
- 2025-09-11: advisory: NVD publication date

## References

- [https://git.kernel.org/stable/c/0d59ce2bfc3bb13abe6240335a1bf7b96536d022](https://git.kernel.org/stable/c/0d59ce2bfc3bb13abe6240335a1bf7b96536d022)
- [https://git.kernel.org/stable/c/1096eb63ecfc8df90b70cd068e6de0c2ff204dfd](https://git.kernel.org/stable/c/1096eb63ecfc8df90b70cd068e6de0c2ff204dfd)
- [https://git.kernel.org/stable/c/43d26997d88c4056fce0324e72f62556bc7e8e8d](https://git.kernel.org/stable/c/43d26997d88c4056fce0324e72f62556bc7e8e8d)
- [https://git.kernel.org/stable/c/81278be4eb5f08ba2c68c3055893e61cc03727fe](https://git.kernel.org/stable/c/81278be4eb5f08ba2c68c3055893e61cc03727fe)
- [https://git.kernel.org/stable/c/87bfabb3b2f46827639173f143aa43f7cfc0a7e6](https://git.kernel.org/stable/c/87bfabb3b2f46827639173f143aa43f7cfc0a7e6)
- [https://git.kernel.org/stable/c/981c845f29838e468a9bfa87f784307193a31297](https://git.kernel.org/stable/c/981c845f29838e468a9bfa87f784307193a31297)
- [https://git.kernel.org/stable/c/9f9967fed9d066ed3dae9372b45ffa4f6fccfeef](https://git.kernel.org/stable/c/9f9967fed9d066ed3dae9372b45ffa4f6fccfeef)

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