isofs: validate block number from NFS file handle in isofs_export_iget
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.
Summary
In the Linux kernel, the following vulnerability has been resolved: isofs: validate block number from NFS file handle in isofs_export_iget isofs_fh_to_dentry() and isofs_fh_to_parent() pass an attacker- controlled block number (ifid->block or ifid->parent_block) from the NFS file handle to isofs_export_iget(), which only rejects block == 0 before calling isofs_iget() and ultimately sb_bread(). A crafted file handle with fh_len sufficient to pass the check added by commit 0405d4b63d08 ("isofs: Prevent the use of too small fid") can still drive the server to read any in-range block on the backing device as if it were an iso_directory_record. That earlier fix was assigned CVE-2025-37780. sb_bread() on an out-of-range block returns NULL cleanly via the EIO path, so there is no memory-safety violation. For in-range reads of adjacent-partition data on the same block device, the unrelated bytes end up in iso_inode_info fields that reach the NFS client as dentry metadata. The deployment surface (isofs exported over NFS from loop-mounted images) is narrow and requires an authenticated NFS peer, but the malformed-file-handle class is reportable as hardening next to the existing CVE-2025-37780 fix. Reject block >= ISOFS_SB(sb)->s_nzones in isofs_export_iget() so the check covers both isofs_fh_to_dentry() and isofs_fh_to_parent() call sites with a single line.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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 | 5.10.237 to before 5.10.258; 5.15.181 to before 5.15.209; 6.1.135 to before 6.1.175; 6.6.88 to before 6.6.140; 6.12.25 to before 6.12.88; 5.4.293 to before 5.5; 6.14.4 to before 6.15 | 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 5.5, 6.15 | Patch available | CNA |
| Linux | Linux | 6.15 and later | 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1 | Patch available | CNA |
- Linux VendorLinux Affected 5.10.237 to before 5.10.258; 5.15.181 to before 5.15.209; 6.1.135 to before 6.1.175; 6.6.88 to before 6.6.140; 6.12.25 to before 6.12.88; 5.4.293 to before 5.5; 6.14.4 to before 6.15 Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 5.5, 6.15 Patch available CNA
- Linux VendorLinux Affected 6.15 and later Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.4.293 to before 5.5; 5.10.237 to before 5.10.258; 5.15.181 to before 5.15.209; 6.1.135 to before 6.1.175; 6.6.88 to before 6.6.140; 6.12.25 to before 6.12.88; 6.14.4 to before 6.15; 6.15.1 to before 6.18.30; 6.19 to before 7.0.7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.15:-:*:*:*:*:*:* | 6.15 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:* | 6.15 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:* | 6.15 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:* | 6.15 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.15:rc6:*:*:*:*:*:* | 6.15 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.15:rc7:*:*:*:*:*:* | 6.15 rc7 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* | 7.1 rc1 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.4.293 to before 5.5; 5.10.237 to before 5.10.258; 5.15.181 to before 5.15.209; 6.1.135 to before 6.1.175; 6.6.88 to before 6.6.140; 6.12.25 to before 6.12.88; 6.14.4 to before 6.15; 6.15.1 to before 6.18.30; 6.19 to before 7.0.7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.15:-:*:*:*:*:*:* Versions 6.15 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:* Versions 6.15 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:* Versions 6.15 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.15:rc5:*:*:*:*:*:* Versions 6.15 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.15:rc6:*:*:*:*:*:* Versions 6.15 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.15:rc7:*:*:*:*:*:* Versions 6.15 rc7 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* Versions 7.1 rc1 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 5.5, 6.15
- Fix · CNA Linux (Linux) Fixed in 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.88, 6.18.30, 7.0.7, 7.1
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-46124
- 2026-10-03 Alias added: GHSA-5599-pvjx-q3hc
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-19 Weakness changed · CISA ADP
- 2026-10-20 Affected versions changed · Red Hat
References
Patch 8
- https://git.kernel.org/stable/c/ee0024f5a7e3c73aa253869fae9650ae054093ca
- https://git.kernel.org/stable/c/31dbb4ba0f719ae7774e4c0c95172c9bf81692f5
- https://git.kernel.org/stable/c/908a76f0b1038035e6ebb4f2293ce079f92e0a02
- https://git.kernel.org/stable/c/bb0988ed4f2e26d59bbb58f644cb3a55b7521e21
- https://git.kernel.org/stable/c/0a1af74ae2177bda3aee0837a0546309aa539d0d
- https://git.kernel.org/stable/c/afbafeddf23db13fe2edb2d5c0bf4bbb13d7881b
- https://git.kernel.org/stable/c/4c721a1d9b3c4fcaf59cc9b2281e3ec5a043e1a6
- https://git.kernel.org/stable/c/24376458138387fb251e782e624c7776e9826796
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Sources
- CVE-2026-46124 · CVE Program
- CVE-2026-46124 · NVD
- FIRST EPSS
- GHSA-5599-pvjx-q3hc · GitHub Advisory Database · CC BY 4.0
- CVE-2026-46124 · Red Hat security data · CC BY 4.0
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