bootconfig: Fix integer overflow in initrd size check
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 4 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: bootconfig: Fix integer overflow in initrd size check Sashiko reported that in get_boot_config_from_initrd(), a crafted initrd with a huge bootconfig size (such as 0xFFFFFFFF) can cause the pointer arithmetic: data = ((void *)hdr) - size; to wrap around on 32-bit systems (or when pointer subtraction overflows). Because data wraps around, the subsequent bounds check: if ((unsigned long)data < initrd_start) evaluates to false, bypassing the check. The kernel then calls xbc_calc_checksum(data, size), which attempts to read 4GB of memory, hitting unmapped pages and triggering a fatal kernel page fault during early boot. Furthermore, on 64-bit systems with an initrd > 4.29 GB, an unbounded 32-bit size can similarly bypass the initrd_start check. Fix this by: 1. Ensuring the initrd is at least large enough to contain the bootconfig footer and verifying hdr is within the initrd bounds. 2. Checking that size does not exceed XBC_DATA_MAX and does not exceed the available space between initrd_start and hdr before performing pointer subtraction.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.7
- Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.112, 6.18.53, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-97906
- 2026-10-03 Alias added: GHSA-rh89-37w4-pmjq
- 2026-10-03 Fix available: Linux/Linux@4d45bc0f8cdf606d5409b5f64a8a6609f6520c03, Linux/[email protected] · CNA
- 2026-10-03 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/[email protected], Linux/Linux@97be05f33f79342ea65d9b99c9ad07a93b8eef5a · CNA
- 2026-10-21 1 new reference · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/97be05f33f79342ea65d9b99c9ad07a93b8eef5a
- https://git.kernel.org/stable/c/4d45bc0f8cdf606d5409b5f64a8a6609f6520c03
- https://git.kernel.org/stable/c/8d4343a411eaa182d323ab5b149496416015f27d
- https://git.kernel.org/stable/c/bff9a1579e2c9b2a59fdf3793becc9d7bf5ff1a6
- https://git.kernel.org/stable/c/7812d6dab0698001e50e8c2f901e17da3eb6f429
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Sources
- CVE-2026-97906 · CVE Program
- CVE-2026-97906 · NVD
- FIRST EPSS
- GHSA-rh89-37w4-pmjq · GitHub Advisory Database · CC BY 4.0
- CVE-2026-97906 · Red Hat security data · CC BY 4.0
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