ftrace: Do not blindly read the ip address in ftrace_bug()
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 3 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 2.6.28 and later | 4.4.273, 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13 | Patch available | CNA |
- Linux VendorLinux Affected 2.6.28 and later Fixed in 4.4.273, 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13 Patch available CNA
CPE configurations NVD · 6
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 2.6.28 to before 4.4.273; 4.5 to before 4.9.273; 4.10 to before 4.14.237; 4.15 to before 4.19.195; 4.20 to before 5.4.126; 5.5 to before 5.10.44; 5.11 to before 5.12.11 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | 5.13 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* | 5.13 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* | 5.13 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* | 5.13 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* | 5.13 rc5 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 2.6.28 to before 4.4.273; 4.5 to before 4.9.273; 4.10 to before 4.14.237; 4.15 to before 4.19.195; 4.20 to before 5.4.126; 5.5 to before 5.10.44; 5.11 to before 5.12.11 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* Versions 5.13 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* Versions 5.13 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* Versions 5.13 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* Versions 5.13 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:* Versions 5.13 rc5 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 4.4.273, 4.9.273, 4.14.237, 4.19.195, 5.4.126, 5.10.44, 5.12.11, 5.13
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-47276
- 2026-10-03 Alias added: GHSA-rgj4-j68m-986v
References
Patch 8
- https://git.kernel.org/stable/c/0bc62e398bbd9e600959e610def5109957437b28
- https://git.kernel.org/stable/c/4aedc2bc2b32c93555f47c95610efb89cc1ec09b
- https://git.kernel.org/stable/c/acf671ba79c1feccc3ec7cfdcffead4efcec49e7
- https://git.kernel.org/stable/c/862dcc14f2803c556bdd73b43c27b023fafce2fb
- https://git.kernel.org/stable/c/7e4e824b109f1d41ccf223fbb0565d877d6223a2
- https://git.kernel.org/stable/c/97524384762c1fb9b3ded931498dd2047bd0de81
- https://git.kernel.org/stable/c/3e4ddeb68751fb4fb657199aed9cfd5d02796875
- https://git.kernel.org/stable/c/6c14133d2d3f768e0a35128faac8aa6ed4815051
More Linux Kernel vulnerabilities
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- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2021-47276 · CVE Program
- CVE-2021-47276 · NVD
- FIRST EPSS
- GHSA-rgj4-j68m-986v · GitHub Advisory Database · CC BY 4.0
- CVE-2021-47276 · Red Hat security data · CC BY 4.0
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