Linux: Double Free
CVE-2026-68192 is a high-severity double free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions 81c58a206d1deee01f4c29236d4154c0872f2a38, 382ee00b2d1e31869ae576a60d3fbe7a2153512f, 739b686aecdb14a6065300ea53401f043e51fd22 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 0.41% 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 81c58a206d1deee01f4c29236d4154c0872f2a38 or 382ee00b2d1e31869ae576a60d3fbe7a2153512f or 739b686aecdb14a6065300ea53401f043e51fd22 or b7d1d8cb1bdca56aecebacd2896615da0acc126a, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, 81c58a206d1deee01f4c29236d4154c0872f2a38; 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, 382ee00b2d1e31869ae576a60d3fbe7a2153512f; 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, 739b686aecdb14a6065300ea53401f043e51fd22; 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, b7d1d8cb1bdca56aecebacd2896615da0acc126a; 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, 5a045c2f0fbf029873d2295178fa0785ade35af0; 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, 044fca8f45ba9ab6ca526163155234cf88287ff5; 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, 0ca80328df23f851c86866720d4977783c919ee6; 4684997d9eea29380000e062755aa6d368d789a3 up to, but not including, 538c51e9d124cf656f2dd0c0394a8545efc7102d; and 1 more ranges | 81c58a206d1deee01f4c29236d4154c0872f2a38, 382ee00b2d1e31869ae576a60d3fbe7a2153512f, 739b686aecdb14a6065300ea53401f043e51fd22, b7d1d8cb1bdca56aecebacd2896615da0acc126a, 5a045c2f0fbf029873d2295178fa0785ade35af0, 044fca8f45ba9ab6ca526163155234cf88287ff5 |
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
- AdjacentThe attacker must be on the same local network segment.
- 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:A/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: wifi: brcmfmac: make release_scratchbuffers idempotent brcmf_pcie_release_scratchbuffers() frees the shared.scratch and shared.ringupd DMA buffers with dma_free_coherent() but does not clear the pointers afterwards, unlike the sibling release_ringbuffers() which NULLs commonrings/flowrings/idxbuf on release. Both the bus_reset .reset callback (brcmf_pcie_reset) and brcmf_pcie_remove() call release_scratchbuffers. When reset teardown has run before removal, remove's own teardown would call dma_free_coherent() a second time on the already-freed DMA allocation. NULL the pointers after free, matching release_ringbuffers(), so a later release observes that the allocation has already been released. This patch makes repeated sequential release safe; the reset-work lifetime is handled separately by the following patch. This issue was found by an in-house static analysis tool.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
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
Other references
- git.kernel.org/stable/c/044fca8f45ba9ab6ca526163155234cf88287ff5
- git.kernel.org/stable/c/0ca80328df23f851c86866720d4977783c919ee6
- git.kernel.org/stable/c/382ee00b2d1e31869ae576a60d3fbe7a2153512f
- git.kernel.org/stable/c/538c51e9d124cf656f2dd0c0394a8545efc7102d
- git.kernel.org/stable/c/5a045c2f0fbf029873d2295178fa0785ade35af0
- git.kernel.org/stable/c/739b686aecdb14a6065300ea53401f043e51fd22
- git.kernel.org/stable/c/81c58a206d1deee01f4c29236d4154c0872f2a38
- git.kernel.org/stable/c/b7d1d8cb1bdca56aecebacd2896615da0acc126a
Recent Double Free vulnerabilities
- 7.8 High severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
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