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Vulnerability · Published Feb 27, 2024 · Assigned by Linux

CVE-2021-46928parisc: Clear stale IIR value on instruction access rights trap

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 86.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux5.15.15-1DEBIAN-CVE-2021-46928
Debian:13linux5.15.15-1DEBIAN-CVE-2021-46928
Debian:14linux5.15.15-1DEBIAN-CVE-2021-46928
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2021-46928
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2021-46928

Affected products (as reported)

VendorProductVersions
Linux Linux 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before d01e9ce1af6116f812491d3d3873d204f10ae0b81da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before e96373f0a5f484bc1e193f9951dcb3adf24bf3f71da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – before 484730e5862f6b872dca13840bed40fd7c60fa26
Linux Linux 2.6.12

References