CVE-2026-46303
HighCVSS 8.2Exploitation Probability (EPSS)
Low risk20th percentile - higher than 20% of all known CVEs
Summary
A vulnerability was found in the Linux kernel's ISO 9660 filesystem (isofs) related to Rock Ridge extension validation. The rock_continue() function reads the extent block number from the CE record without checking if it is within the mounted volume bounds, potentially allowing out-of-range reads or reads from an adjacent filesystem.
Risk Assessment
The risk involves a potential information leak via readlink() from an adjacent filesystem on the same block device, which could be exploited by an attacker with the ability to mount a crafted ISO image (e.g., via udisks2 or CAP_SYS_ADMIN).
Recommendation
Immediately update the Linux kernel to a version containing the fix that adds extent block number validation in rock_continue() against the volume size (s_nzones).
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: isofs: validate Rock Ridge CE continuation extent against volume size rock_continue() reads rs->cont_extent verbatim from the Rock Ridge CE record and passes it to sb_bread() without checking that the block number is within the mounted ISO 9660 volume. commit e595447e177b ("[PATCH] rock.c: handle corrupted directories") added cont_offset and cont_size rejection for the CE continuation but did not validate the extent block number itself. commit f54e18f1b831 ("isofs: Fix infinite looping over CE entries") later capped the CE chain length at RR_MAX_CE_ENTRIES = 32 but again left the block number unchecked. With a crafted ISO mounted via udisks2 (desktop optical auto-mount) or via CAP_SYS_ADMIN mount, rs->cont_extent can therefore point at an out-of-range block or at blocks belonging to an adjacent filesystem on the same block device. sb_bread() on an out-of-range block returns NULL cleanly via the block layer EIO path, so there is no memory-safety violation. For in-range reads of adjacent- filesystem data, the CE buffer is parsed as Rock Ridge records and only the text of SL sub-records reaches userspace through readlink(), which makes the info-leak channel narrow and difficult to exploit; still, rejecting the malformed CE outright matches the rejection shape already present in the same function for cont_offset and cont_size. Add an ISOFS_SB(sb)->s_nzones bounds check to rock_continue() next to the existing offset/size rejection, printing the same corrupted-directory-entry notice.