{"id":"CVE-2024-26736","state":"PUBLISHED","title":"afs: Increase buffer size in afs_update_volume_status()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Increase buffer size in afs_update_volume_status()\n\nThe max length of volume->vid value is 20 characters.\nSo increase idbuf[] size up to 24 to avoid overflow.\n\nFound by Linux Verification Center (linuxtesting.org) with SVACE.\n\n[DH: Actually, it's 20 + NUL, so increase it to 24 and use snprintf()]","publishedAt":"2024-04-03T17:00:22.693Z","updatedAt":"2026-08-05T11:26:55.027Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux 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Increase buffer size in afs_update_volume_status()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Increase buffer size in afs_update_volume_status()\n\nThe max length of volume->vid value is 20 characters.\nSo increase idbuf[] size up to 24 to avoid overflow.\n\nFound by Linux Verification Center (linuxtesting.org) with SVACE.\n\n[DH: Actually, it's 20 + NUL, so increase it to 24 and use snprintf()]"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d2ddc776a4581d900fc3bdc7803b403daae64d88","status":"affected","lessThan":"5c27d85a69fa16a08813ba37ddfb4bbc9a1ed6b5","versionType":"git"},{"version":"d2ddc776a4581d900fc3bdc7803b403daae64d88","status":"affected","lessThan":"d9b5e2b7a8196850383c70d099bfd39e81ab6637","versionType":"git"},{"version":"d2ddc776a4581d900fc3bdc7803b403daae64d88","status":"affected","lessThan":"e56662160fc24d28cb75ac095cc6415ae1bda43e","versionType":"git"},{"version":"d2ddc776a4581d900fc3bdc7803b403daae64d88","status":"affected","lessThan":"e8530b170e464017203e3b8c6c49af6e916aece1","versionType":"git"},{"version":"d2ddc776a4581d900fc3bdc7803b403daae64d88","status":"affected","lessThan":"6e6065dd25b661420fac19c34282b6c626fcd35e","versionType":"git"},{"version":"d2ddc776a4581d900fc3bdc7803b403daae64d88","status":"affected","lessThan":"d34a5e57632bb5ff825196ddd9a48ca403626dfa","versionType":"git"},{"version":"d2ddc776a4581d900fc3bdc7803b403daae64d88","status":"affected","lessThan":"6ea38e2aeb72349cad50e38899b0ba6fbcb2af3d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/volume.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.15","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.15","versionType":"semver"},{"version":"5.4.270","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.211","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.150","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.80","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.19","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.7.7","status":"unaffected","lessThanOrEqual":"6.7.*","versionType":"semver"},{"version":"6.8","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/volume.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/5c27d85a69fa16a08813ba37ddfb4bbc9a1ed6b5"},{"url":"https://git.kernel.org/stable/c/d9b5e2b7a8196850383c70d099bfd39e81ab6637"},{"url":"https://git.kernel.org/stable/c/e56662160fc24d28cb75ac095cc6415ae1bda43e"},{"url":"https://git.kernel.org/stable/c/e8530b170e464017203e3b8c6c49af6e916aece1"},{"url":"https://git.kernel.org/stable/c/6e6065dd25b661420fac19c34282b6c626fcd35e"},{"url":"https://git.kernel.org/stable/c/d34a5e57632bb5ff825196ddd9a48ca403626dfa"},{"url":"https://git.kernel.org/stable/c/6ea38e2aeb72349cad50e38899b0ba6fbcb2af3d"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The value formatted into the undersized stack buffer originates entirely from a remote Volume Location server's `VL.GetEntryByNameU` reply (`ntohl(uvldb->volumeId[i])`, fs/afs/vlclient.c:77), and the call into `afs_update_volume_status()` is itself forced on demand by a remote fileserver returning VNOVOL/VMOVED abort codes (fs/afs/rotate.c:247,387). AFS VL traffic is unauthenticated rxrpc over UDP, so a rogue cell server or an on-path response spoofer reaches this code across the network.\nAC:H - Overflowing `idbuf[16]` requires `volume->vid` to exceed 10 decimal digits, but the on-wire `volumeId[]` field is `__be32` (fs/afs/afs_vl.h:123) and is the sole source of `volume->vid`, capping it at `4294967295`. The wire-format width is a hard constraint entirely beyond the attacker's control, so no attainable input triggers the write.\nPR:N - The attacker is the VL server (or a network entity spoofing its unauthenticated replies) and holds no account, credential, or capability on the target host. No local privilege on the victim is consumed anywhere along the `afs_select_fileserver` → `afs_check_volume_status` → `afs_update_volume_status` path.\nUI:N - On a configured AFS client `/afs` is already mounted at boot, and the volume-status refresh fires from routine background revalidation and from server-supplied VMOVED/VNOVOL responses without any victim action. The attacker drives the update himself via the fileserver's abort codes.\nS:U - Any corruption is confined to the AFS client's own kernel stack frame within the same kernel security authority. No VM, hypervisor, IOMMU, or sandbox boundary is crossed.\nC:H - A stack write past `idbuf` overwrites the adjacent locals in the same frame — the `new`/`old`/`discard`/`vldb` pointers and `idsz` — and corrupting `vldb` or `idsz` redirects the subsequent `memcmp`/`memcpy` of the volume name and the `afs_alloc_server_list()` walk, yielding an attacker-influenced kernel read. Per kernel guidance, memory corruption leverageable for disclosure is scored High.\nI:H - This is an out-of-bounds stack write, which per kernel guidance is High: the clobbered pointers are dereferenced and written through immediately afterwards (`memcpy(volume->name, vldb->name, AFS_MAXVOLNAME)`, `rcu_assign_pointer(volume->servers, new)`), giving a path to controlled kernel memory modification and control-flow influence.\nA:H - On any stack-protector kernel the 5-byte overrun smashes the canary and `__stack_chk_fail()` panics the machine; without it, the corrupted `vldb`/`new`/`old` pointers are dereferenced and freed (`kfree(vldb)`, `afs_put_serverlist()`), producing an oops. Either outcome is a full kernel crash."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:26:55.027Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"5.4.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"5.10.211"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"5.15.150"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.1.80"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.6.19"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.7.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.15","versionEndExcluding":"6.8"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-26736","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-04-05T17:35:04.677455Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-06-04T17:48:32.562Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/5c27d85a69fa16a08813ba37ddfb4bbc9a1ed6b5","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/d9b5e2b7a8196850383c70d099bfd39e81ab6637","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/e56662160fc24d28cb75ac095cc6415ae1bda43e","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/e8530b170e464017203e3b8c6c49af6e916aece1","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/6e6065dd25b661420fac19c34282b6c626fcd35e","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/d34a5e57632bb5ff825196ddd9a48ca403626dfa","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/6ea38e2aeb72349cad50e38899b0ba6fbcb2af3d","tags":["x_transferred"]},{"url":"https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-02T00:14:12.959Z"}}]}}}