Linux: Use After Free
CVE-2026-64303 is a critical-severity use after free vulnerability in Linux, 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 ad370d1c7a9a832f77b2341513cd31188c9443af, cce2063404b2341e7b2bbf85eddfcd70a31a0033, af39a2698f69b584d14a00cffe0f51a2caa15337 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 0.69% chance of exploitation within 30 days, higher than 54% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Linux to ad370d1c7a9a832f77b2341513cd31188c9443af or cce2063404b2341e7b2bbf85eddfcd70a31a0033 or af39a2698f69b584d14a00cffe0f51a2caa15337 or e65505d91fa036a238968e4c10744244d1b968c4, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, 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 |
|---|---|---|---|
| Linux | Linux | 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, ad370d1c7a9a832f77b2341513cd31188c9443af; 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, cce2063404b2341e7b2bbf85eddfcd70a31a0033; 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, af39a2698f69b584d14a00cffe0f51a2caa15337; 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, e65505d91fa036a238968e4c10744244d1b968c4; 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, d5c1060218a3749c8a18b36f8169d910fce20639; 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, 808033d80d5c9f8adf7e8de9317389270ce13430; 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, 9d000bdd250d649a11cd7f733175686877344582; 09c04466ce7ea494993c0635ba5edb6d2222a806 up to, but not including, 01980b5da56e573d62798d0ff6c86bcaa2b22cbe; and 1 more ranges | ad370d1c7a9a832f77b2341513cd31188c9443af, cce2063404b2341e7b2bbf85eddfcd70a31a0033, af39a2698f69b584d14a00cffe0f51a2caa15337, e65505d91fa036a238968e4c10744244d1b968c4, d5c1060218a3749c8a18b36f8169d910fce20639, 808033d80d5c9f8adf7e8de9317389270ce13430 |
| Linux | Linux Kernel | 5.2 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.4 | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39 |
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 CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: spi: fsl-lpspi: terminate the RX channel on TX prepare failure path When dmaengine_prep_slave_sg() fails for the TX channel, the error path terminates the TX DMA channel but leaves the RX channel running. Since the RX channel was already submitted and issued prior to preparing the TX descriptor, returning -EINVAL causes the SPI core to unmap the DMA buffers while the RX DMA engine continues writing to them, leading to potential memory corruption or use-after-free. Terminate the RX channel before returning on the TX prepare failure path.
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: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/01980b5da56e573d62798d0ff6c86bcaa2b22cbe
- git.kernel.org/stable/c/808033d80d5c9f8adf7e8de9317389270ce13430
- git.kernel.org/stable/c/9d000bdd250d649a11cd7f733175686877344582
- git.kernel.org/stable/c/ad370d1c7a9a832f77b2341513cd31188c9443af
- git.kernel.org/stable/c/af39a2698f69b584d14a00cffe0f51a2caa15337
- git.kernel.org/stable/c/cce2063404b2341e7b2bbf85eddfcd70a31a0033
- git.kernel.org/stable/c/d5c1060218a3749c8a18b36f8169d910fce20639
- git.kernel.org/stable/c/e65505d91fa036a238968e4c10744244d1b968c4
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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