net/mlx5: Fix MCIA register buffer overflow on 32 dword reads
CVE-2026-68293 · published 10 Aug 2026
How serious is it
- Severity: high, CVSS score 7.1 out of 10.
- No exploit prediction (EPSS) score yet.
- Not on the CISA list of exploited vulnerabilities.
- No public exploit in Exploit-DB.
Is your app affected by CVE-2026-68293?
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Who is affected
- Linux Linux: 271907ee2f29cd1078fd219f0778fd824fb1971c to < c8a4acc19dcdc83e1303c29d9535e5c99415a2e3, 271907ee2f29cd1078fd219f0778fd824fb1971c to < 5be4eebd5a3a198dab0adcd550e1cadca79bdfed, 271907ee2f29cd1078fd219f0778fd824fb1971c to < 87b39a8c875ca744b7de69af0a8ef8874cffccf1, 271907ee2f29cd1078fd219f0778fd824fb1971c to < 88b2a16ddac3357e3f1d528e758b51e2c945d546
- Linux Linux: 5.18
How to check
- Find out whether you run the affected product and which version, then compare it with the versions above.
How to fix
Copies a prompt for Claude Code, Cursor or Codex that asks it to check whether you run this product.
- Apply the vendor's update or mitigation from the references below. If there is none yet, limit exposure of the affected service until there is.
- If a vulnerable version was live, check your logs and rotate the secrets that server could read.
The advisory
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Fix MCIA register buffer overflow on 32 dword reads
The MCIA register can return up to 32 dwords (128 bytes) when the device
advertises the mcia_32dwords capability, but struct
mlx5_ifc_mcia_reg_bits only defines dword_0..11, leaving room for just
12 dwords (48 bytes) of data.
mlx5_query_mcia() clamps the read size to mlx5_mcia_max_bytes() and then
memcpy()s that many bytes out of the register, potentially reading past
the end of the 'out' buffer. On kernels built with FORTIFY_SOURCE this
is caught as a buffer overflow while reading the module EEPROM via
ethtool:
detected buffer overflow in memcpy
kernel BUG at lib/string_helpers.c:1048!
RIP: 0010:fortify_panic+0x13/0x20
Call Trace:
mlx5_query_mcia.isra.0+0x200/0x210 [mlx5_core]
mlx5_query_module_eeprom_by_page+0x4a/0xa0 [mlx5_core]
mlx5e_get_module_eeprom_by_page+0xbb/0x120 [mlx5_core]
eeprom_prepare_data+0xf3/0x170
ethnl_default_doit+0xf1/0x3b0
Extend the mcia_reg layout to 32 dwords.
Check your whole app
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References
- git.kernel.org/stable/c/c8a4acc19dcdc83e1303c29d9535e5c99415a2e3
- git.kernel.org/stable/c/5be4eebd5a3a198dab0adcd550e1cadca79bdfed
- git.kernel.org/stable/c/87b39a8c875ca744b7de69af0a8ef8874cffccf1
- git.kernel.org/stable/c/88b2a16ddac3357e3f1d528e758b51e2c945d546
- git.kernel.org/stable/c/11c057d23465c7a5817a7284c896d19d54c0b616
Merged from CVE List. Last updated 25 Oct 2026. All vulnerabilities · RSS · JSON