CVE-2026-64317

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.