5.5

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

Modified
AliasesUBUNTU-CVE-2021-46928DEBIAN-CVE-2021-46928
Published 27-02-2024Last modified 11-05-2026

Vulnerability summary

CVE-2021-46928 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 13.2% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.22%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 27-02-2024
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

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 metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.22% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu62 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < d01e9ce1af6116f812491d3d3873d204f10ae0b8 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < e96373f0a5f484bc1e193f9951dcb3adf24bf3f7 | ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 484730e5862f6b872dca13840bed40fd7c60fa26 | 2.6.12
  • linux_kernel< 5.10.90 | ≥ 5.11.0, < 5.15.13
Debian1 product
  • linux< 5.15.15-1

3 vendors · 65 products

References

7 links