CVE Catalog

CVE-2026-64317

HighCVSS 7.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.16%

6th percentile - higher than 6% of all known CVEs

Summary

In the Linux kernel's isofs filesystem, a vulnerability was found in the handling of Rock Ridge symbolic links. An attacker can craft an ISO image that triggers an out-of-bounds read of up to 255 bytes of kernel memory, which is then copied to user space via readlink().

Risk Assessment

The risk is a leak of sensitive kernel memory (e.g., keys, passwords) to an unprivileged user who mounts a malicious ISO image. Automatic mounting by desktop environments (e.g., udisks2) enables the attack without special privileges.

Recommendation

Apply the Linux kernel patch that fixes the isofs vulnerability immediately. If not possible, temporarily disable automatic mounting of ISO images or restrict access to optical drives.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS