CVE-2021-47276: ftrace: Do not blindly read the ip address in ftrace_bug()
Vulnerability summary
CVE-2021-47276 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.7% of scored vulnerabilities.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 6 · Related 6Timeline
- 21-05-2024PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: ftrace: Do not blindly read the ip address in ftrace_bug() It was reported that a bug on arm64 caused a bad ip address to be used for updating into a nop in ftrace_init(), but the error path (rightfully) returned -EINVAL and not -EFAULT, as the bug caused more than one error to occur. But because -EINVAL was returned, the ftrace_bug() tried to report what was at the location of the ip address, and read it directly. This caused the machine to panic, as the ip was not pointing to a valid memory address. Instead, read the ip address with copy_from_kernel_nofault() to safely access the memory, and if it faults, report that the address faulted, otherwise report what was in that location.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.24%
Chance of exploitation in the next 30 days
Percentile
15%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.24% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu86 products
- linuxAll versions (No fix recorded) | < 4.15.0-156.163 | < 5.4.0-81.91
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 4.15.0-1111.118 | < 5.4.0-1055.58
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < 0bc62e398bbd9e600959e610def5109957437b28 | ≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < 4aedc2bc2b32c93555f47c95610efb89cc1ec09b | ≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < acf671ba79c1feccc3ec7cfdcffead4efcec49e7 | ≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < 862dcc14f2803c556bdd73b43c27b023fafce2fb | ≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < 7e4e824b109f1d41ccf223fbb0565d877d6223a2 | ≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < 97524384762c1fb9b3ded931498dd2047bd0de81 | ≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < 3e4ddeb68751fb4fb657199aed9cfd5d02796875 | ≥ 05736a427f7e16be948ccbf39782bd3a6ae16b14, < 6c14133d2d3f768e0a35128faac8aa6ed4815051 | 2.6.28
- linux_kernel≥ 2.6.28, < 4.4.273 | ≥ 4.5, < 4.9.273 | ≥ 4.10, < 4.14.237 | ≥ 4.15, < 4.19.195 | ≥ 4.20, < 5.4.126 | ≥ 5.5, < 5.10.44 | ≥ 5.11, < 5.12.11 | 5.13:rc1 | 5.13:rc2 | 5.13:rc3 | 5.13:rc4 | 5.13:rc5
Debian1 product
- linux< 5.10.46-1
3 vendors · 89 products
