Linux: Out-of-bounds Read
CVE-2026-64317 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 1015e1c4b2fadd9c09704e24738e46598778c869, 36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee, a22cb6bb54dc167047ea9e70d97dfbc2c15649e3 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 1015e1c4b2fadd9c09704e24738e46598778c869 or 36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee or a22cb6bb54dc167047ea9e70d97dfbc2c15649e3 or b736b12108fd116c41777628f5a333791604df26, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 1015e1c4b2fadd9c09704e24738e46598778c869; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, a22cb6bb54dc167047ea9e70d97dfbc2c15649e3; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, b736b12108fd116c41777628f5a333791604df26; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 6bf41db09ef935d76fcc84ccf213b42c18de95ee; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, b5699642640d6cff357638738c5293985cd5a53d; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 9830725078c8483c6831ec10222ae724806ea36b; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 up to, but not including, 5fa1d6a5ec2356d2107dead614437c66fa7138b1; and 1 more ranges | 1015e1c4b2fadd9c09704e24738e46598778c869, 36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee, a22cb6bb54dc167047ea9e70d97dfbc2c15649e3, b736b12108fd116c41777628f5a333791604df26, 6bf41db09ef935d76fcc84ccf213b42c18de95ee, b5699642640d6cff357638738c5293985cd5a53d |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 2.6.12.1 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.4; 2.6.12 | 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: isofs: bound Rock Ridge symlink components to the SL record get_symlink_chunk() and the SL handling in parse_rock_ridge_inode_internal() walk the variable-length components of a Rock Ridge "SL" (symbolic link) record. Each component is a two-byte header (flags, len) followed by len bytes of text, so it occupies slp->len + 2 bytes. Both loops read slp->len and advance to the next component, and get_symlink_chunk() additionally does memcpy(rpnt, slp->text, slp->len), but neither checks that the component lies within the SL record before dereferencing it. A crafted SL record whose component declares a len that runs past the record (rr->len) therefore triggers an out-of-bounds read of up to 255 bytes. When the record sits at the tail of its backing buffer - for example a small kmalloc()ed continuation block reached through a CE record - the read crosses the allocation; get_symlink_chunk() then copies the out-of-bounds bytes into the symlink body returned to user space by readlink(), disclosing adjacent kernel memory. ISO 9660 images are routinely mounted from untrusted removable media - desktop environments auto-mount them (e.g. via udisks2) without CAP_SYS_ADMIN - so the record contents are attacker-controlled. Reject any component that does not fit in the remaining record bytes before using it. In get_symlink_chunk() return NULL, like the existing output-buffer (plimit) checks, so a malformed record makes readlink() fail with -EIO rather than silently returning a truncated target; in parse_rock_ridge_inode_internal() stop the inode-size walk.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/1015e1c4b2fadd9c09704e24738e46598778c869
- git.kernel.org/stable/c/36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee
- git.kernel.org/stable/c/5fa1d6a5ec2356d2107dead614437c66fa7138b1
- git.kernel.org/stable/c/6bf41db09ef935d76fcc84ccf213b42c18de95ee
- git.kernel.org/stable/c/9830725078c8483c6831ec10222ae724806ea36b
- git.kernel.org/stable/c/a22cb6bb54dc167047ea9e70d97dfbc2c15649e3
- git.kernel.org/stable/c/b5699642640d6cff357638738c5293985cd5a53d
- git.kernel.org/stable/c/b736b12108fd116c41777628f5a333791604df26
Other references
Recent Out-of-bounds Read vulnerabilities
- 8.4 High severity
- 7.1 High severity
- 7.1 High severity
- 7.7 High severity
- 9.1 Critical severity
- 8.2 High severity
Spotted an error? Tell us.