CVE-2021-46928
In the Linux kernel, the following vulnerability has been resolved: parisc: Clear stale IIR value on instruction access rights trap When a trap 7 (Instruction access rights) occurs, this means the CPU couldn't execute an instruction due to missing…
Does this matter?
Lower severity and a low EPSS score (0.22%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: parisc: Clear stale IIR value on instruction access rights trap When a trap 7 (Instruction access rights) occurs, this means the CPU couldn't execute an instruction due to missing execute permissions on the memory region. In this case it seems the CPU didn't even fetched the instruction from memory and thus did not store it in the cr19 (IIR) register before calling the trap handler. So, the trap handler will find some random old stale value in cr19. This patch simply overwrites the stale IIR value with a constant magic "bad food" value (0xbaadf00d), in the hope people don't start to try to understand the various random IIR values in trap 7 dumps.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.22% probability · 13th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-755
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/484730e5862f6b872dca13840bed40fd7c60fa26Patch
- https://git.kernel.org/stable/c/d01e9ce1af6116f812491d3d3873d204f10ae0b8Patch
- https://git.kernel.org/stable/c/e96373f0a5f484bc1e193f9951dcb3adf24bf3f7Patch
- https://git.kernel.org/stable/c/484730e5862f6b872dca13840bed40fd7c60fa26Patch
- https://git.kernel.org/stable/c/d01e9ce1af6116f812491d3d3873d204f10ae0b8Patch
- https://git.kernel.org/stable/c/e96373f0a5f484bc1e193f9951dcb3adf24bf3f7Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.