{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38657","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-04-16T04:51:24.030Z","datePublished":"2025-08-22T16:01:00.512Z","dateUpdated":"2026-08-05T12:03:43.959Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:03:43.959Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: rtw89: mcc: prevent shift wrapping in rtw89_core_mlsr_switch()\n\nThe \"link_id\" value comes from the user via debugfs.  If it's larger\nthan BITS_PER_LONG then that would result in shift wrapping and\npotentially an out of bounds access later.  In fact, we can limit it\nto IEEE80211_MLD_MAX_NUM_LINKS (15).\n\nFortunately, only root can write to debugfs files so the security\nimpact is minimal."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H","baseScore":7.3,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The only attacker-controlled path into `rtw89_core_mlsr_switch()` is a local `write()` to `/sys/kernel/debug/ieee80211/phyX/rtw89/mlo_mode`; the driver's other caller derives `link_id` from a bitmap already bounded by `IEEE80211_MLD_MAX_NUM_LINKS`, and no received frame or remote peer data reaches this function.\nAC:L - The attacker picks `link_id` outright, and the mod-64 shift wrap plus the `rtwvif->links[link_id]` over-index happen deterministically on every write — no race, no memory grooming. The only precondition is an MLD vif with a usable-but-inactive link, which is the ordinary steady state of Wi-Fi 7 hardware associated in MLSR mode and can be re-attempted at will.\nPR:L - The driver deliberately creates `mlo_mode` world-writable (`rtw89_debugfs_add_rw` uses `S_IFREG | 0666`) beneath 0755 directories, so on the embedded, BMC and Android-derived images that mount debugfs 0755 for diagnostics any unprivileged local user can trigger it; no `capable()` check exists anywhere in the rtw89 debugfs write path. Low is chosen over High per the higher-severity-when-uncertain rule, consistent with prior kernel CNA scoring of world-accessible debugfs files (CVE-2025-38719).\nUI:N - The attacker performs the single debugfs write themselves and the out-of-bounds access occurs synchronously in their own `write()` syscall; no victim must open a file, associate, or take any other action.\nS:U - The out-of-bounds reads and the resulting fault stay entirely within the kernel's own security authority — no hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - This is not a bounded few-byte over-read: `rtwvif->links[link_id]` reads a pointer from an attacker-chosen offset up to ~32 GB past a 15-entry array, and the recovered value is dereferenced as a `struct rtw89_vif_link *` whose `mac_id` is shipped to the Wi-Fi firmware, whose `link_id` is printed to dmesg, and whose `chanctx_idx` drives a second unchecked `hal->chanctx[idx]` over-read — an unbounded, repeatable kernel-memory disclosure primitive.\nI:L - No out-of-bounds write or write-through-pointer exists on this path, but values harvested from out-of-bounds kernel memory are programmed into the device: a bogus `mac_id` is sent to the Wi-Fi firmware in an H2C MLO link-cfg command and an out-of-range `chanctx_idx`/`phy_idx` steer TXGAPK/IQK/TSSI/DPK calibration writes to RF and BB registers, modifying radio state in ways the attacker cannot precisely steer.\nA:H - Dereferencing the garbage pointer read from far outside `links[]` — for `mac_id`, `chanctx_idx` and `phy_idx` — readily oopses the kernel (and KASAN reports the out-of-bounds access outright), while surviving cases run RF calibration with nonsense parameters that can wedge the adapter; the write can be repeated at will and escalates to a panic under `panic_on_oops`."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/wireless/realtek/rtw89/core.c"],"versions":[{"version":"9dd85e739ce0765f022014c3e0713e1007d7ef60","lessThan":"417cfa9cc44fbe6bceab786f9a4ee5a210f1288e","status":"affected","versionType":"git"},{"version":"9dd85e739ce0765f022014c3e0713e1007d7ef60","lessThan":"53cf488927a0f79968f9c03c4d1e00d2a79731c3","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/wireless/realtek/rtw89/core.c"],"versions":[{"version":"6.16","status":"affected"},{"version":"0","lessThan":"6.16","status":"unaffected","versionType":"semver"},{"version":"6.16.1","lessThanOrEqual":"6.16.*","status":"unaffected","versionType":"semver"},{"version":"6.17","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.16.1"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.16","versionEndExcluding":"6.17"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/417cfa9cc44fbe6bceab786f9a4ee5a210f1288e"},{"url":"https://git.kernel.org/stable/c/53cf488927a0f79968f9c03c4d1e00d2a79731c3"}],"title":"wifi: rtw89: mcc: prevent shift wrapping in rtw89_core_mlsr_switch()","x_generator":{"engine":"bippy-1.2.0"}}}}