High severity · published Jul 25, 2026
CVE-2026-64317
isofs: bound Rock Ridge symlink components to the SL record
7.1
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 7% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
2.6.12.1 before 5.10.261; 5.11 before 5.15.212; 5.16 before 6.1.178; 6.2 before 6.6.145; 6.7 before 6.12.96; 6.13 before 6.18.39; +6 more · source: NVD
LI
Linux · Linux
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 1015e1c4b2fadd9c09704e24738e46598778c869; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before a22cb6bb54dc167047ea9e70d97dfbc2c15649e3; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b736b12108fd116c41777628f5a333791604df26; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 6bf41db09ef935d76fcc84ccf213b42c18de95ee; 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b5699642640d6cff357638738c5293985cd5a53d; +3 more · source: vendor
SS
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7; V3.1.6; V3.1.7 · source: CISA
SS
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7; V3.1.6; V3.1.7 · source: CISA
SS
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP · Siemens
V3.1.6; V3.1.7 · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-64317
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-64317
Patch
https://git.kernel.org/stable/c/1015e1c4b2fadd9c09704e24738e46598778c869
Patch
https://git.kernel.org/stable/c/36fe7d25dbc40da0c6b1dd4513a4f69ac6164eee
Patch
https://git.kernel.org/stable/c/5fa1d6a5ec2356d2107dead614437c66fa7138b1
Patch
https://git.kernel.org/stable/c/6bf41db09ef935d76fcc84ccf213b42c18de95ee
Patch
https://git.kernel.org/stable/c/9830725078c8483c6831ec10222ae724806ea36b
Patch
https://git.kernel.org/stable/c/a22cb6bb54dc167047ea9e70d97dfbc2c15649e3
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