Linux: Use After Free
CVE-2026-31485 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6, ca4483f36ac1b62e69f8b182c5b8f059e0abecfb, e3fd54f8b0317fbccc103961ddd660f2a32dcf0b as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6 or ca4483f36ac1b62e69f8b182c5b8f059e0abecfb or e3fd54f8b0317fbccc103961ddd660f2a32dcf0b or adb25339b66112393fd6892ceff926765feb5b86, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.253 or 5.15.203 or 6.1.168 or 6.6.131, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6; 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, ca4483f36ac1b62e69f8b182c5b8f059e0abecfb; 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, e3fd54f8b0317fbccc103961ddd660f2a32dcf0b; 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, adb25339b66112393fd6892ceff926765feb5b86; 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, d5d01f24bc6fbde40b4e567ef9160194b61267bc; 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, e89e2b97253c124d37bf88e96e5e8ce5c3aeeec3; 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, 15650dfbaeeb14bcaaf053b93cf631db8d465300; 5314987de5e5f5e38436ef4a69328bc472bbd63e up to, but not including, b341c1176f2e001b3adf0b47154fc31589f7410e; and 1 more ranges | fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6, ca4483f36ac1b62e69f8b182c5b8f059e0abecfb, e3fd54f8b0317fbccc103961ddd660f2a32dcf0b, adb25339b66112393fd6892ceff926765feb5b86, d5d01f24bc6fbde40b4e567ef9160194b61267bc, e89e2b97253c124d37bf88e96e5e8ce5c3aeeec3 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.5 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 4.10.1 up to, but not including, 5.10.253; 5.11 up to, but not including, 5.15.203; 5.16 up to, but not including, 6.1.168; 6.2 up to, but not including, 6.6.131; 6.7 up to, but not including, 6.12.80; 6.13 up to, but not including, 6.18.21; 6.19 up to, but not including, 6.19.11; 4.10; and 1 more ranges | 5.10.253, 5.15.203, 6.1.168, 6.6.131, 6.12.80, 6.18.21 |
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
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: spi: spi-fsl-lpspi: fix teardown order issue (UAF) There is a teardown order issue in the driver. The SPI controller is registered using devm_spi_register_controller(), which delays unregistration of the SPI controller until after the fsl_lpspi_remove() function returns. As the fsl_lpspi_remove() function synchronously tears down the DMA channels, a running SPI transfer triggers the following NULL pointer dereference due to use after free: | fsl_lpspi 42550000.spi: I/O Error in DMA RX | Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [...] | Call trace: | fsl_lpspi_dma_transfer+0x260/0x340 [spi_fsl_lpspi] | fsl_lpspi_transfer_one+0x198/0x448 [spi_fsl_lpspi] | spi_transfer_one_message+0x49c/0x7c8 | __spi_pump_transfer_message+0x120/0x420 | __spi_sync+0x2c4/0x520 | spi_sync+0x34/0x60 | spidev_message+0x20c/0x378 [spidev] | spidev_ioctl+0x398/0x750 [spidev] [...] Switch from devm_spi_register_controller() to spi_register_controller() in fsl_lpspi_probe() and add the corresponding spi_unregister_controller() in fsl_lpspi_remove().
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/15650dfbaeeb14bcaaf053b93cf631db8d465300
- git.kernel.org/stable/c/adb25339b66112393fd6892ceff926765feb5b86
- git.kernel.org/stable/c/b341c1176f2e001b3adf0b47154fc31589f7410e
- git.kernel.org/stable/c/ca4483f36ac1b62e69f8b182c5b8f059e0abecfb
- git.kernel.org/stable/c/d5d01f24bc6fbde40b4e567ef9160194b61267bc
- git.kernel.org/stable/c/e3fd54f8b0317fbccc103961ddd660f2a32dcf0b
- git.kernel.org/stable/c/e89e2b97253c124d37bf88e96e5e8ce5c3aeeec3
- git.kernel.org/stable/c/fbe6f40caeebb0b1ea9dfedc259124c1d3cda7a6
Other references
Recent Use After Free vulnerabilities
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