CVE-2024-47742: debian debian_linux Path Traversal

Vulnerability summary

CVE-2024-47742 is a high (CVSS 7.8) Path Traversal vulnerability in debian debian_linux. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.1% of scored vulnerabilities.

Timeline

1. 21-10-2024
   PublishedVulnerability first disclosed.
2. 05-08-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: firmware_loader: Block path traversal Most firmware names are hardcoded strings, or are constructed from fairly constrained format strings where the dynamic parts are just some hex numbers or such. However, there are a couple codepaths in the kernel where firmware file names contain string components that are passed through from a device or semi-privileged userspace; the ones I could find (not counting interfaces that require root privileges) are: - lpfc_sli4_request_firmware_update() seems to construct the firmware filename from "ModelName", a string that was previously parsed out of some descriptor ("Vital Product Data") in lpfc_fill_vpd() - nfp_net_fw_find() seems to construct a firmware filename from a model name coming from nfp_hwinfo_lookup(pf->hwinfo, "nffw.partno"), which I think parses some descriptor that was read from the device. (But this case likely isn't exploitable because the format string looks like "netronome/nic_%s", and there shouldn't be any *folders* starting with "netronome/nic_". The previous case was different because there, the "%s" is *at the start* of the format string.) - module_flash_fw_schedule() is reachable from the ETHTOOL_MSG_MODULE_FW_FLASH_ACT netlink command, which is marked as GENL_UNS_ADMIN_PERM (meaning CAP_NET_ADMIN inside a user namespace is enough to pass the privilege check), and takes a userspace-provided firmware name. (But I think to reach this case, you need to have CAP_NET_ADMIN over a network namespace that a special kind of ethernet device is mapped into, so I think this is not a viable attack path in practice.) Fix it by rejecting any firmware names containing ".." path components. For what it's worth, I went looking and haven't found any USB device drivers that use the firmware loader dangerously.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.