{"id":"CVE-2026-68206","state":"PUBLISHED","title":"media: v4l2-ctrls: validate HEVC active reference counts","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: v4l2-ctrls: validate HEVC active reference counts\n\nHEVC slice parameters are shared stateless V4L2 controls, but the common\nvalidation path does not verify the active L0/L1 reference counts before\ndriver-specific code consumes them.\n\nThe original report came from Cedrus, but the active count bounds are\nnot Cedrus-specific. Validate them in the common HEVC slice control path\nso stateless HEVC drivers get the same basic guarantees as soon as the\ncontrol is queued.\n\nDo not reject ref_idx_l0/ref_idx_l1 entries here. Existing userspace may\nuse out-of-range sentinel values such as 0xff for missing references, and\nsome hardware can use that information for concealment. Keep this common\ncheck limited to the active reference counts.","publishedAt":"2026-08-10T12:00:25.309Z","updatedAt":"2026-10-19T20:58:57.229Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"3299c3905f3fb439ebd892658b87bc76c93ae116","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"9a998cc1c348769262d433acb7d238c5fac4b2e0","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"dbaf0e0023e2f9332c5164822def7f80b7d2c5ef","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"3068ab802fc98b121dcb451e1f7f4d338ffc7a19","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"b01df98a6669d2b67d8aed816021b327fd905998","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"afbe4bc252d90a6f8fad869b06d5430f615f22f9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/v4l2-core/v4l2-ctrls-core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.14","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/v4l2-core/v4l2-ctrls-core.c"]}],"references":["https://git.kernel.org/stable/c/3299c3905f3fb439ebd892658b87bc76c93ae116","https://git.kernel.org/stable/c/9a998cc1c348769262d433acb7d238c5fac4b2e0","https://git.kernel.org/stable/c/dbaf0e0023e2f9332c5164822def7f80b7d2c5ef","https://git.kernel.org/stable/c/3068ab802fc98b121dcb451e1f7f4d338ffc7a19","https://git.kernel.org/stable/c/b01df98a6669d2b67d8aed816021b327fd905998","https://git.kernel.org/stable/c/afbe4bc252d90a6f8fad869b06d5430f615f22f9"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68206.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68206","state":"PUBLISHED","datePublished":"2026-08-10T12:00:25.309Z","dateUpdated":"2026-10-19T20:58:57.229Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-30T09:28:09.374Z"},"containers":{"cna":{"title":"media: v4l2-ctrls: validate HEVC active reference counts","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: v4l2-ctrls: validate HEVC active reference counts\n\nHEVC slice parameters are shared stateless V4L2 controls, but the common\nvalidation path does not verify the active L0/L1 reference counts before\ndriver-specific code consumes them.\n\nThe original report came from Cedrus, but the active count bounds are\nnot Cedrus-specific. Validate them in the common HEVC slice control path\nso stateless HEVC drivers get the same basic guarantees as soon as the\ncontrol is queued.\n\nDo not reject ref_idx_l0/ref_idx_l1 entries here. Existing userspace may\nuse out-of-range sentinel values such as 0xff for missing references, and\nsome hardware can use that information for concealment. Keep this common\ncheck limited to the active reference counts."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"3299c3905f3fb439ebd892658b87bc76c93ae116","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"9a998cc1c348769262d433acb7d238c5fac4b2e0","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"dbaf0e0023e2f9332c5164822def7f80b7d2c5ef","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"3068ab802fc98b121dcb451e1f7f4d338ffc7a19","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"b01df98a6669d2b67d8aed816021b327fd905998","versionType":"git"},{"version":"d395a78db9eabd12633b39e05c80e803543b6590","status":"affected","lessThan":"afbe4bc252d90a6f8fad869b06d5430f615f22f9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/v4l2-core/v4l2-ctrls-core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.14","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/media/v4l2-core/v4l2-ctrls-core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/3299c3905f3fb439ebd892658b87bc76c93ae116"},{"url":"https://git.kernel.org/stable/c/9a998cc1c348769262d433acb7d238c5fac4b2e0"},{"url":"https://git.kernel.org/stable/c/dbaf0e0023e2f9332c5164822def7f80b7d2c5ef"},{"url":"https://git.kernel.org/stable/c/3068ab802fc98b121dcb451e1f7f4d338ffc7a19"},{"url":"https://git.kernel.org/stable/c/b01df98a6669d2b67d8aed816021b327fd905998"},{"url":"https://git.kernel.org/stable/c/afbe4bc252d90a6f8fad869b06d5430f615f22f9"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The control is only settable through VIDIOC_S_EXT_CTRLS on the local V4L2 stateless decoder node (/dev/videoN), followed by QBUF/STREAMON on the same fd. There is no network or remote path into the HEVC slice-params control.\nAC:L - The attacker supplies num_ref_idx_l0/l1_active_minus1 verbatim as a u8; any value in 16..254 deterministically drives the loops in cedrus_h265_is_low_delay() and rkvdec_hevc set_ps_field() out of bounds on the very next decode run. No race, timing window, or uncontrollable memory layout is involved.\nPR:L - Only an unprivileged local account holding the video device node is required (typically the 'video' group, or the media/codec service reachable from sandboxed apps on Android and embedded Allwinner/Rockchip devices). cedrus_try_ctrl() checks only SPS chroma format and bit depth; no capability or root check exists on the path.\nUI:N - The attacking process performs the whole sequence itself: open the decoder, set the crafted HEVC slice-params control, queue buffers and start streaming. No victim action, media file, or mount is needed.\nS:U - The out-of-bounds accesses stay inside the kernel's own slab and DMA memory within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - decode_params->dpb[] holds 16 16-byte entries at the tail of a ~336-byte control allocation, so an index up to 255 reads roughly 3.8 KB of adjacent kernel heap; the pred-weight loops likewise read 240 bytes past slice_params. Those OOB bytes are fed into decoder SRAM and steer the low-delay decision, giving an attacker-steerable oracle over unrelated kernel memory.\nI:H - In rkvdec-hevc, REF_PIC_IDX_L0(i)/REF_PIC_LONG_TERM_L1(i) with i up to 255 resolve to bit offset ~1276 in an 8-word rkvdec_rps_packet, so set_ps_field() performs an out-of-bounds write of attacker-chosen bits at an attacker-chosen offset into (and past the end of) the coherent DMA priv_tbl, corrupting hardware descriptor state and adjacent memory.\nA:H - Reading several kilobytes past a slab object can walk into an unmapped or poisoned region and trips KASAN/hardening checks, while the rkvdec out-of-bounds write corrupts the DMA table handed to the decoder; either yields a kernel oops or wedged hardware, repeatable at will from an unprivileged process."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-19T16:31:26.837Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-68206","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:45:53.723010Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","type":"CWE","description":"CWE-20 Improper Input Validation"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:58:57.229Z"}}]}}}